It's okay for you to make that offer and it is okay for her to refuse it. If you gave her 3k and she cleaned your house 36 times, that seems about even, like you are prepaying for her work.

It's also okay for you to decide that you don't want to give her 3k after all, which is what I would decide. If you do give it to her, just do it without conditions and forget about it. You aren't going to be able to hold her to anything. It seems a bit ... rude? on her part to ask you for help and then get upset when you offer her a job instead of a freebie.