They will eventually tell you
you will know that he likes your friend because he will always bring her up and he will want to be around her.
don't
Your friend tells you.
Be honest, and ask him.
ask him
how he lookes at you
Woman's intuition. Actually, talk to the guy or have your friend guy talk to him for you.
Tell her the truth.
She likes you and that other guy and her boyfriend but does not know who she likes best.
If your guy friend likes you tell him how you feel about it. If you like him let him know. If you don't, break it to him easily but not to easy that way he understands and you still have a friendship.
Ask him what he likes about you. Maybe he likes your personality, your jokes, or your hobbies.
You wont know until other rumors, if your friends knows that a guy likes you, and if they talk, your friend and the guy, that means the guy wants it to keep it a secret and told your friend to keep it as a secret, if he/she does that means he/she is a good friend to the guy, so wait until the guy asks you out, theres nothing for you to worry about