If a dude confesses thru a letter, he either totally digs the girl, or is a complete lame ass. Only confess your feelings if she completely is into you and you've both had sex already. None of that "Hey, I have a crush on you" crap. Be a man and walk up to her, tell her she's going to hang with you, because you are a hot catch, and she has won the Kain6th Lottery. Okay, so that might not be your style, but what I'm trying to say, is be up front. Be fun with her, and don't go confessing your love to a new girl. It conveys that you are not worthy of her. I write my Girlfriend letters every month or so, letting her know that she's the most amazing woman I've met (which is true) but not in those words, and yes, I am positive that she is head over heels about me as well.