When it wore off and she woke in the middle of that night - Tyrion was awake and reading - he slept poorly , Sansa knew that . " Poor Margaery , " she said softly almost to herself , but her lord husbands hearing was sharp . " You do n't envy her ? "
Question: How does Tyrion know that Sansa Does n't envy Marjaery ?
The answer to the above question:


She seems rueful and sad about Marjaery .