reason for the ending of "the lady or the tiger"

The princess could not bring herself to let her lover marry another person,so she showed the man the door which she knew had a tiger in it knowing that he would trust her.However after witnessing her lover's death,the princess became regretful as she had just killed her lover,and wanted join him.

The Lady,or the Tiger?

For a moment,everyone in the arena stopped breathing,with all eyes on the door which the man was opening.The whole arena was so quiet that even the sound of an ant crawling on the floor could be heard.When the door was opened,there came a sound of a lady's feet shuffling towards the man.Everyone cheered happily and some even hugged each other as they found out that the man's life was safe.Out of the blue,a ferocious tiger pounced out of the darkness onto the man.The audience was stunned by this sight,they all gave a sigh that such a young,handsome and innocent life was lost.Just then,tears came rolling down from the princess's face,she thought remorsefully upon seeing the corpse of her lover,"How could I do this!I just killed my lover!""Don't worry my love,I will join you soon!"