Lyric discussion by micr0phone 

Cover art for Sing lyrics by Graduate, The

this is a gorgeous song.

he cares strongly for a girl, but doesn't feel that he's ready to have a relationship. he's caught up in trying to figure himself out--"i'm somewhere in between who i am and who i want to be". he sees that she is such an amazing girl and tells her not to wait around for him. he says that her heart "can sing in a key that fits with anything", meaning that she can find love anywhere, so why would she wait around for him?

basically, he feels inadequate & that he will never be good enough for her, but he cares for her regardless.