What song is this chorus from? Props for answer!

Baby,you light up my world like nobody else
The way that you flip your hair gets me overwhelmed
But when you smile at the ground it ain't hard to tell,
You don't know,oh oh,you don't know your beautiful.
If only you saw what I could see,
You'd understand why I want you so desperatly
Right now I'm looking at you and I can't believe,
You don't know,oh oh,you don't know your beautiful,oh oh,
But that's what makes you beautiful.

5 props for the right answer.