This has absolutely nothing to do with the manhwa but...whatever!

She.. is.. not.. straight..
If you like her, date her. If not you need to bluntly tell her off

I like her but still not sure if i do as a bff or a woman. I've talked with her before and she cried telling me not to stop being her friend and to ignore the fact that she likes me so that we can still be bestfriend like before. Honestly i feel soo bad for her like i can't just say smth like 'You like me,right? Well,i don't. So....lets stop being friends'

1. She's not as straight as she claims lol.
2. It seems like you're confused on how you feel. I think you need to sort out your feelings first. When you do, if you like her as a friend, you have to make it clear that you don't like her in that way. You can be gentle about it and let her down easy. Like telling her how you see her as a friend, and her crush on you doesn't deter you from wanting to keep your relationship as friends. It's better if you let her know soon, so she can move on and find happiness with someone else. It will be awkward and she will be hurt, but it's better for her to know so she can move on. Right now, she's in a depressing situation.
3. I wouldn't make out with her anymore, even if she asks, because stuff like that can give her a mixed signal that you have feelings for her and if your truly don't, then it would come off that way. It's like a blessing and a curse for her. She gets a great present (in her mind), but its disheartening because she knows that you're not hers and knowing that hurts.
4. If you do have feelings for her, then explore them.

Hope that helps!

The other persons advice is really great. You don't need to break off your friendship.it's not easy, but it's possible. What you should never do though is date her for her sake.

THANK YOU FOR YOUR ADVICE!!!*mwah*