Whats something cute i can write in a little note to the girl i like?

today I was walking in the hall with the girl I like and she tore off a piece of her notebook and wrote on it "sup bro :) <3" and it was really cute the way she did it. So tomorrow I kinda want to do the same thing back but idk what to put on the note I'm thinking something like "you make me smile" or "your pretty" or something small and short like that but I want it to be good. Any suggestions?