"Truth" for us common people is not in the "real world reflected as it is", but only in the felicitous encounter of our common sense with the World.
Truth is for persons the representation they more or less suitably understand as obvious, reliable and reasonable and thus believe to be the actual state of things.
Like it or not but this is a commonsense definition of truth and it will not go away in spite of tomes of erudite precision and perfect standards.
Truthfulness indicates when people represent to other people what they actually believe and feel and intend. When we judge whether or not people "speak truth", sincerity opposed to lying is a fairer moral scale than "objective" knowledge. Moral if not scientific. They may be scientifically or philosophically false because of being misinformed or cheated, by ignorance or error, more usually they are imprecise or superficial; but they speak in truth, to their best. Shouldn't we account sincerity - how one's words and deeds fit that which he genuinely believes - in the scales of truth?
The truth-of-sincerity is precious and unavoidable because it validates the reliability of most things we ever learn and know; simply because the bulk of our knowledge comes to us by means of witnessing. We trust the sincere and mistrust the dishonest.
Scientific authorities explain with good argument - and we trust them too - that beliefs expressed are true exclusively when they are objectively verified by an infallible third party, by something independent of us all. My, I could never have opened my mouth in my whole life, waiting for such perfection!
In common everyday talk there is often confusion between the two meanings of the word truth; as knowledge consisting in beliefs technically and rationally justified and truth understood as the sincere communication of whatever one believes. I find this confusion harmful and sometimes ill intended. Offending too. Knowing that someone is in error should not be represented as them being guilty against truthfulness.
Among us, naive common thinkers* living on limited planes of land where the World looks mainly flat, truth requires first of all our sincerity – that which is not concealed; something uttered for others to understand, feel and accept as credible, as it is for us; presenting things as we are convinced of them to be. Such is the meaning of expressing your truth, the certainty for which you would risk your hand to get cut by Divinity in the Mouth of Truth at Santa Maria.
Your experience, your modest beliefs more or less scientifically, philosophically and religiously attested, are your truth which you own and disclose;
To be called truth, your truth longs to be made known to other people. This "making known" which is mere freedom of expression deserves respect provided it is in good faith and open-minded enough to suffer the expression of different truth which appears erroneous to you. You are not obliged to give in or accept that which you do not believe, this is not an invitation to relativism, only to mutually respectful plurality. For the sake of peace and diversity.
Except though from due respect those fundamentalist worshippers of the cult of truth without doubt who would sacrifice everything else, and especially other people, to exclusive beliefs. Their truth grows quickly from received or personal to unique and universal - the one Faith, the One Reality, the only one. These close-minded people make me count the wonderful urge of truth among the great sources of man-made evil.
Seen as the supreme value of Humanity truth becomes a feral idea, an idea of prey.
Monothetic, one eyed truth irresistibly devours humaneness, good life, freedom, compassion, everything which keeps us human. The truth of absolute unshakeable reason or faith let loose to bully communities and nations engulfs everything, even itself. It weeds off whatever thinking which moves. Paradoxically, when only one such truth rules among people in flesh and bones, it fathers unavoidable falsity, as a condition to survive. Sooner or later it urges to burn books and people. Or to replace people with machines.
Deadly contagion charges ahead astride absolute Truth, like the four horsemen of Apocalypse, whenever there is only one allowed. Other people’s sincere beliefs become - from mere inevitable imprecisions, misunderstandings, points of view or errors - madness, inferior ignorance that must be redressed by force, or worse, wicked lies to punish, crimes of thought. As Will Durant wrote in his synthesis of the History of Civilisation "certainty is murderous" [1a]
Sometimes, and quite often, one’s most important truthful belief is undecidable, beyond possible proof for or against it. Who has a moral right to judge such conviction, in lack of evidence, for somebody else?
Personal certainty, if reduced forcefully to the realm of observable evidence would make the human mind sadly poor and slavish.
Scientific truth about the world as it is – is an effort of detached, coherent reason applied to the exploration of fact. You are justified to believe something after you verify it objectively and formulate it logically. Even that solid truth keeps being proven false from time to time, as it is still obtained by categories reflecting our nature of human beings, not by the stars.
Huge progress as it proves to be, the scientific view of the world shows today some disquieting signs of unquestioned faith in unique vulgar-materialistic truth; when it disqualifies any truthful conviction unfit to its Method. Reason obtained its own much deserved public freedom a few centuries ago but now it cannot tolerate without mocking that which is not true for science and reason. This is strange; psychology understood long ago that the living person is a mixture of reason and irrationality but it is not able to take that into account. Instead, during the whole Twentieth Century "the science of psychology" served, coldly, as the unique value, a truth purified as much as possible from any human colour. What it could not measure, experiment materially and account for, independent of people, it belittled and even declared non-existent. What it did not understand yet, it declared irrelevant. In many "disciplines" when meeting ignorance and error, the average scientist still shows today arrogance and paternalism. Luckily, the non-scientific are not burnt at the stake but I believe that human knowledge is crippled and progress slowed down in many scientifically incorrect fields.
Sincerity has much to do with revealed religious truth, or with political convictions which are largely based on norm, authority, trust and unquestioned belief accepted from authority and witnessing of credible leaders, parents and from tradition. One feels true or not against those convictions. Political and religious faiths, respectable as they are, proved already how bloody they can be when they reign or when they collide. When religions (and ideologies) coexist civilization flourishes. If one alone prevails it suffers only silent slaves. Should not the truth of reason learn toleration as all creeds must do?
TRUTH, be it personal, revealed or scientific is in all its forms, beyond all doubts, our fine, vital value and affirming, what we believe or not is the emblem of human freedom. However, what about other people’s freedom, when they deem as truth what we know for certain and see as error? Do we allow them a right to be wrong?
The paradox is that, intuitively, my best, unquestionable, justified, truth, the one made sacred because it is proved by Science, Faith, Political creed, or - closer - by my life experience, my eyes and ears, by my life, by my hard earned Business, leaves no place for another. Whatever differs from it is error. Be it, but then, we need a tolerant rule of conduct concerning error. We may need special education to suffer absurdity, irrationality, the incomprehensible, without growing insecure and mad and aggressive.
As Tibor Machan found the tendency,  “We have no choice but to think that everyone with whom we seriously disagree is wrong.” He found that others, the wrong ones, are usually considered “not favoured with the truth by God,.. mislead by the devil,.. too stupid of feeble minded to grasp the truth... brain-damaged... victims of various obsessions, in desperate need to be different or rebellious.” In the best case they must be improperly or incompletely informed or too lazy and wishful to think things over. Some of these explanations may be right sometimes but the whole seems to me terribly suspect: rational but unreasonable.
I do not feel able of certainty about the cause of such different and irreconcilable beliefs of what constitutes truth in important matters; maybe some free, undecidable choices are involved or some unaccounted differences in logical level, values, culture and point of view. When I look at truth as a person, I see first of all a moral value. This value should have an obligation to coexist, reasonably if not rationally, with other moral values like respect, freedom and peace.
If you have a birth right to exist you also have the right to draw a line anytime and to believe here and now what seems certain and justified to you and to express your truth; and also to say that you do not believe that which you don’t. Provided that you listen truly when other people come with their truth or claim to prove that you are not right; that you respect the same rights of other people when you do not believe their beliefs.
What counts for me more than why contradictory "truths" are professed, is to choose what to wisely do when we face such diversity.
My life solution is practical, moral and emotional, fit for everyday life: to attest that I listen and hear the difference, to agree respectfully that we disagree and to affirm the right to be wrong, as long as one does not force ones unquestioned belief on other people and while requesting the respect to be mutual; to live calmly in the presence of dissonance, contradiction and error without an urge to kill. This requires a belief that diversity and otherness are good. It also requires self-control and much practice.
* You will imagine that I do not tackle this great subject of the philosophers with a pretense that I know better. What I seek is common sense leading to practical wisdom that would make our life better.
 La Bocca della Verità (Photo cc Roughneck) at the portico of the church of Santa Maria in Rome, Italy. The legend of the Mouth is its role as a lie detector; in the Middle Ages, folklore has asserted that if one told a lie with his hand in the mouth of the sculpture, it would be bitten off.
[1a] "Intolerance is the natural concomitant of strong faith; tolerance grows only when faith loses certainty; certainty is murderous." Durant, W The Story of Civilisation, Vol IV - The Age of Faith, Simon and Schuster, New York, 1950, p. 784
 Künne, Wolfgang, Conceptions of Truth, Oxford University Press, Oxford, New York, 2003
 Machan Tibor, Why is Everybody Else Wrong? - Explorations in Truth and Reason, Springer, New York, 2011