Based on the clues given in the story, does the princess send the young man to the lady or to the tiger in "The Lady or the Tiger?"

Based on the clues, it is likely that the princess sent her lover to his death.
Stockton tells us that this story is a sort of personality test.  However, it seems that there is plenty of evidence that the princess has her lover killed. Stockton spends a lot of time telling us about her nature. He tells us that the semi-barbaric king has a semi-barbaric daughter.

This semi-barbaric king had a daughter as blooming as his most florid fancies, and with a soul as fervent and imperious as his own. As is usual in such cases, she was the apple of his eye, and was loved by him above all humanity.

The description “semi-barbaric” means that both of them are very passionate and a little bit savage. When the king finds out that the princess has a lover, he is very angry. His reaction is to throw the lover upon his system of justice, the arena. In the arena, the princess knows that he will choose one of two doors. One door will produce a tiger, and the other will produce a lady. Which does she choose?

The more we reflect upon this question, the harder it is to answer. It involves a study of the human heart which leads us through devious mazes of passion, out of which it is difficult to find our way.

If she chooses the tiger, it is because she cannot stand for him to have the lady. We are told that she knows who the lady is and is jealous of her. That seems like a good enough reason to believe that she chooses the tiger. She is jealous, she is not deeply in love with this boy, and she is a passionate but not particularly sentimental girl. She most likely chooses the tiger, and the boy goes to his death.