Promises are funny things. Like bones. They can be strong enough to save lives, or easily broken -- ground into powder. And he likes the weak kinds best of all.
He wants to grind her into powder. Because, pretty or not, she gets in the way far too often, now. She wants to know things she shouldn't, wants to do things she usually wouldn't.
It's really too bad that girls have to come with brains. Especially girls as pretty as she is.