Often a girl will want a guy to be a F.I.N.O.. this may be due to an advance rejected, or the guy not being at a proper social, or economic status.
The purpose of which is to allow a person to say they are friends with someone else, but never actually be a friend and interact with them.
girl: i think its better, don't you?
guy: i don't see how we can be friends in that scenario.
girl we can be. there!
guy: i'm no F.I.N.O.
girl: what's that?
guy: a friend in name only.