The just friends trap is absolutely NOT going to get her back, ever. The reason she asked for that is because she isn’t sure she wants the breakup. Asking you to be just friends gives her the opportunity to keep you on her hook as a backup plan while she tries other options. Nobody ever goes to the backup plan, there are always other options. She will eventually ween herself off you completely and you will be the one hurt.
Also Just Friends, makes you look weak and needy. You are basically cuckolded and letting her walk all over you. Not attractive at all. But don’t beat yourself up, we have all been there before. The important thing is you are here now and you recognize that this isn’t working for you.
This is what you do; explain to her politely but firmly that this just friends thing isn’t working for you and you are going to move on with your life and she should do the same. Wish her the best then go no contact. She isn’t going to like that, because you are her safety net and she wants that safety net. She might get angry, if she does, don’t respond negatively. Simply say “I am sorry you feel that way, but I think this is for the best” then stop talking. Hopefully she will respect your decision and not fight you.
What is going to happen is when you make that decision and go no contact, you are projecting to her that you are a confident, secure man who doesn’t have time for games. You are just fine without her and know you will have no problem finding another woman who sees your value and wants more than a measly “just friends”. This is going to look incredibly attractive to her. She will resist the temptation for as long as she can, but I am confident that you are going to be in her thoughts and she will be wrestling with her decision.
Eventually her doubts and curiosity will overpower her stubbornness and she will reach out to you with the intentions of seeing if she can get you back. When that happens, keep your emotions under control and keep the conversation casual. Getting emotional and telling her you still love her and all that is going to make you look needy and show her that this was just a game.
Do not just sit around and wait for her. Work on yourself, do things you enjoy and be happy. This will make you attractive to her when she comes back or to any other woman who catches your eye. Humans are attracted to happy, confident people.
If she gets angry when you take your power back by telling her you are ending the just friends things, do not respond immediately. Show restraint and maturity. Allow at least a few hours to go by before you tell something like I said above. If she continues fighting with you, or whatever else she might say that you are not sure how to respond to, again do not respond immediately. Take your time, think it through. If you still aren’t sure, post here and maybe we can help.