I assume that you need a hook for an essay on "The Lady or the Tiger".  To find a hook, I would first do an outline of what you want to say in your essay.  Are you going  to explain why you believe the man found the tiger behind the door?  For what reasons is that your belief?   Does it have to do with jealousy at watching her man be married to another?  Do you believe that the princess is a bit savage like her father?  Or do you believe that she sent her man to the door with a woman behind it?  Would she be willing to watch as her man was taken by another to save his life?  When you have found your own beliefs  about the princess and organized your paper, then you can find your hook.  Perhaps it will have to do with being brave and loyal to someone you love.  Perhaps you will ask your reader if he or she has ever had to do something very difficult and were happy or sad at the results.  Perhaps you find that jealousy is the most powerful emotion and can lead to regretted or positive decisions.  Good luck with your paper.