Sugars that aren't readily absorbed into your bloodstream hang around to become food for unhealthy bacteria. There is no common sugar that is more likely to cause GERD than fructose, the principal sugar in fruit and high-fructose corn syrup. Table sugar, incidentally, is a mixture of fructose and glucose, and for this reason should be avoided by people who have acid reflux disease. Honey also contains fructose.
Sugar alcohols, products such as erythritol, isomalt, lactitol, mannitol, maltitol, sorbitol, and xylitol, do not raise blood sugar levels because they are poorly absorbed, but their poor absorption makes them a problem for fermentation in the intestines. Every brand of stevia (including Stevie Blend, SweetLeaf, and Truvia) uses one of these ingredients to “cut” the stevia so it can be measured (the actual amount of stevia in a stevia sweetener is about 0.2% of the contents of the package) and to counteract bitterness. This means that stevia can aggravate GERD, too.
If you are going to use an artificial sweetener, the product least likely to cause problems with GERD is sucralose, which is also known as Splenda. This no-calorie sweetener can't be digested by either people or bacteria, so it won't cause bloating or gas or aggravate heartburn. But wouldn't it be best if you could do without any kind of sweeteners at all?