"Because I said so"

I am trying to figure out the name and artist who sings a slow song that played near the end of the movie when Mandy Moore and Diane Keaton's character's are all sad and mopey. It's not Love by Matt White. Another one. I might just have to go see the movie again if I can't figure it out ! Please help !

Thanks
Melissa

mcoetzee, March 2, 2007; 2:47 PM