"confused" is right, she has to want it. Anyone can stop an addiction (cutting is one) for other people, but it probably won't last and won't be for the right reasons. Try not to sound like you are being an authority figure (most people don't like that), but just talk, let her know you are there for her whenever she needs it, night or day. Let her use you to talk things out, get whatever it is that's on her mind out in the open or just to be there with her. It might help the transition from cutting to not, with a person there with her to help with the ruff parts. It's hard to talk about it, even with the people you love the most, it's not the funnest subject to discuss, but once you know the person you are talking to really does want to help and isn't judging, it makes it a bit easier.
hope everything works out for you.
Never give up,
Never give in,
but making mistakes
is Never a sin