We were in the same predicament as well.
When we hired our helper, we asked if she had any debt and explained to her that a non-negotiable in our home was loan sharks. We explained that we understood sometimes emergencies cropped up and in such situations, rather than she resorting to a loan shark, we would prefer if she came to us first instead. We emphasised the fact that we could not guarantee loaning her money and that it would be based on case-to-case basis and depending on the amount. We also warned her about never ever being a guarantor to her friends' loans.
We also sat down with her to work out what her financial goals are and how to save which she found extremely helpful. We have also signed her up for YWCA's course on Financial Literacy which starts in July. When I first showed her the course information, she felt she didn't need it. However after understanding a little more about planning her financial goals, she approached me again to ask if she could take the course.
We have not had any issue so far and everything has been good. We paid her on a weekly basis for the first month so that she would have some money for her days off.