I don't remember much of the song.

I know it starts off with a man, talking about a female, then she cuts in singing(kind of high pitched) "I fall in loveeeee with youuuu” and he raps back “you can't be in love, I don't believe in love” and then starts into the rap.

I've googled it forever. All I ever get is Elvis, dido, and eminem, all of which are not it. I do believe its not a “well known song”