I can't remember the name of a song, it's artist, it's lyrics, or how it goes!! Help?

The song says something about putting up a wall... she wants to be with him, but he keeps running from her. She says that one day she'll get through, and at the end of the chorus that all she wants is him. I don't remember, it's driving me crazy!! I think the artist is a Kate, Katie, or Kelly. (Not Kelly Clarkson)