A death spirit in love

A death spirits next assignment is to look after a young girl until it's her time to pass and he must kill her. Yet everyday he's with her he gets a feeling in his head, stomach, and strangely his heart. He doesn't know what this feeling is, what to do with it, or how to react to it. It's not his fault he's having these feelings, but there is a consequence when he can't kill her and its not a consequence for just him.