Oh wow! Ok maybe you should just sit her down and explaine to her that your not gay, and [idk if u like her or not] but just try and give [the truth] a semi logical reason for avoiding her kiss. And try and be friends with her?? idk. Thats just what i would do. I hope the situation works out however you want it to. :] goodluck:]

I absolutely have no experience in this kind of problems so I don't know if I will be of much help.

I would suggest the same thing as @UnknownEcho. Have a talk with her and ask her why she did it to clear any misunderstanding.

If the response is something like "I wanted to confirm you're gay" or something along those lines, calmly explain you're not. You already told her that and that you would really appreciate if she stopped claiming that.
Also, try to make her understand your point of view. Just as she wouldn't like being kissed by any random person in a random place, you don't want to be kissed like that.

Obviously, she can reply differently. You'll have to think for other possible replies.

So, yes, have a chat with her, listen to her (because if you want to be listened, you must listen too), and clear up things.
You can be friends again and everyone most probably forget in a week or so.
It's ok to be embarras.sed. I would have totally freaked out if someone did that to me.

Don't get too fixated on the problem. Stay strong and good luck!

Oh, I just read your last painting's description. I didn't know your friend was gay.
I see you're in a really awkward situation. (Sorry, I analyzed the problem in a totally different context).

Considering she's your friend, she must feel really awkward too.
Still, have a chat with her and
keep treating her the same way you always do. Maybe when the awkawardness dies, she'll start to cheer up.

I know, buddy, it gets a bit shocking when a girl wants to kiss you, and you don't know what to do. Just explain to everyone whom misheard and tell them that you are not, by any means, gay nor carry any homosexuality.