What song is this chorus from? Requisiten for answer!

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

5 Requisiten for the right answer.