The only way to know is for him to tell you.
No one can prove that you are gay unless you admit it. Only you know if you are or not. As much as we may stereotype of make assumptions, we cannot know for sure if you are gay or not until you tell.
How do you prove he is gay? Stop being ignorant.
You shouldn't have to PROVE that you're gay. If you are romantically or sexually attracted to members of the opposite sex, then you are gay.
It depends on what you're comparing them to (e. g. "not the same as.....")
well if you wanna know if hes gay ask him if he likes Barbra Walters! and about the cheating ask him if he has any friends in San Francisco then youl know
Just ask
Do not pay any attention to that. If you are gay, you are. If you are not, you could prove it.
there is no possible way to prove anyone is "gay" without asking. Now someone can tell you that this person had sexual relations with them, but that doesnt necessarily mean they are gay
well you know some girls that are gay are "dikes" they dress as boy, tomboys are usually mistaken, cause it isn't usual to others seeing that, but don't worry, just don't care what anyone says and prove you arent. and that's all that matters
Justin Bieber is not gay. He just has a lot of haters using the word "gay" to mean stupid or dumb.
If you are gay, just be completely honest with him. I am a straight guy, but I have a friend who is gay, so I do know this. Just tell him that you understand that he is straight, but that you have feelings for him and you wanted him to know because you felt that you needed to tell him.
There are no real ways to prove you are not gay, as some gays are in 'the closet' and do sleep with woman. It shouldn't really matter what people think, and if it's your friends you shouldn't need to prove you're not. If they're making you prove it they're not good friends.