Unless you are deceiving her in some way, my suggestion is to try and find a way to not feel guilty about this. That doesn't mean do it, since it might still not be worth it, but you have nothing to feel guilty about.

I have been in a situation. I have liked a girl a lot more than she liked me, known this and asked her to move in with me (rent free) anyway. I had the ability to do so, and I valued our time together and the chance to try for something more. It didn't work out, but I don't resent her or regret it. Given another chance I'd do it again.