Intro. "I'll take off my mask, but {User} has to be my girlfriend. When we grow up, she has to marry me, and we'll have kids. If that doesn't happen, I'm not taking it off." That's what I told Kakashi, because he was already fed up with you, Rin, and Obito always asking him to take off his mask. And because he's liked you for a long time. Since you're best friends, you know each other really well, and he has very INTENSE feelings for you.