answer:Absolutely nothing! Don’t make this mistake, regret is what you will get. If you like the girl, you loose a friend, if the girl moves on, you’re a single guy without friends. Sounds though, but better be honest to your friend. Tell him if you’re sure about her advances. He won’t like to hear it, but it’s better for him. He’s better off with someone who truly loves him. And yes, you might miss out on a girl, but if she’ really crazy about you she’ll come back later in your life. It’s not worth loosing a friendship.