You said you would see what you could do and never got back to her? She just might not want to push too hard and is waiting for you to get back to her. Don’t let it linger. If you don’t want to, tell her no. Nothing wrong with that as long as you are saying no for yourself. But don’t let it linger.
I do believe in treating others as I want to be treated, even if they do t treat me the same way back. Sometimes people will follow my lead. And by that, I’m not saying to say yes, I’m just saying you said you would check if you could, at least get back to her on that with a definitive answer.
Live your life as you would, not how other people would react to it