In my experience, these women fall into two broad categories if they're ripe for play: They're either in need of some extra cash, or they're bored and they have an itch that they want scratched. The approach you take is totally different in each case. The first category is easy - just mention the generosity of guys who get a little bit extra fun. The second category is more touchy but can result in a superlative provider. I've found in that case the last thing you want to do is to talk about money - many of these MTs who play would be horrified to think that they were thought of as engaging in prostitution. They're just offering a little more fun on the side, and they're often the ones who REALLY get into it.
In either case, the clients you hook them up with initially will determine whether or not the conversion sticks. They need to be experienced, well-mannered, not-pushy guys who understand the meaning of YMWV. And as I've heard from MT friends of mine, not all hobbyists who frequent MTs fall into this category.
Since you want to keep the worlds apart, you should be very selective about the trusted guys you point in her direction, and you shouldn't let her know that you're involved at all. And make sure these are guys who can take "no" for an answer. Send one, get his feedback, then determine whether or not to send others. If she does come to the dark side, you might share an experience or two with her, or you could just satisfy your voyeuristic side and observe her transformation from afar.
(Sorry for the late bump. Just found this thread, and I've had the pleasure of bringing a woman or several to the dark side.)