I need an idea for a story for a writing cl!!!?

Okay, so in a writing thing, I have to write a story. It has to be about a princess who can't smile or something, and the king calls a meeting, and three sons volunteer, and only the youngest succeeds. what are some ideas for the princess ideas? examples are the princess who wouldn't cry, or the princess who wouldn't sleep. I don't want to use those ideas though because those are examples she gave us, and I want to be more original. Also, it could be about a dragon terrorizing the kingdom or a wolf who steals the sheep. Again, those are examples she gave us, and I want to be original and NOT have those be my story ideas. Thank you so much!