I really can't understand what motivates people to pay for a class and then not want to do the work for it. I understand when high school students cheat, because they really just don't care and are forced to be there. I don't approve of this, but I understand the motivation to just get out. But I don't understand why someone bothers paying for and taking a class if they aren't interested in learning anything from it.
Integral, stop being a push over! Don't wait for her to come to you again, either walk over yourself and tell her you were trying to be polite in your refusal before, but since she didn't take the hint, and seems to have the notion in her head that you're going to do the work for her, you have to be more blunt about it, that you just aren't going to do her work for her.
If you feel like you can't do that without caving in again, then take hypatia's suggestion, and leave her papers for her in an envelope with a note saying you will not do her homework for her.
You don't need to offer any reasons or explanations, just tell her, "No."
Once you've clearly told her no, if she tries yet again, I really think you're fully justified to simply take those papers and toss them into the recycling bin. Actually, if she tries to hand them to you, I think that's what you should tell her as well, that if she leaves them with you again, you're going to toss them right into the recycling bin.
I have to admit, this is way over the top of anything I've ever known anyone to do. I've known people to copy answers from classmates or more often to swap answers (two students each do half the assignment and then swap), but this is the first I've known of someone actually just handing an assignment over for someone else to do for them. Makes you wonder about her integrity on the job, doesn't it?
I agree with BobG. This woman will probably have exceptional business skills if she actually had something to sell. This is probably a required course for her and she doesn't believe it is vital to her goals. Unfortunately for you, and for her, she doesn't have much in the way of morals. She will keep pressuring unless it is made VERY clear to her that this behavior will not be tolerated. I'm sure she will then attempt to make you look like the bad guy, spread gossip, make rumors, perhaps sabotage. CYOA.
As she is acting in her own interests I think you should act in yours. What are your interests? It seems you have some strong moral/ethical objections to doing her homework for her and I don't blame you. I'd be outraged!
What I'm not certain of is why you are having difficulty in refusing her. What are you afraid of? Does her opinion of you matter so much, or is it your own opinion of yourself that would change? It's not really her that you are confronting. It is your own fear.
In a way this is an interesting opportunity for you. What choice would give you long term peace with yourself? I really do believe that in the long run you will feel better about yourself if you kindly, yet FIRMLY declare your position on the matter to her as soon as possible. (She will claim she didn't have time to finish her work if you wait much longer, or some such excuse. She will find someone else to do her homework but that is not your responsibility.)Are you trying to take responsibility for her?