Ethics first.
It is never okay to play with somebody's heart or to lead them on if you have no true intentions. And quite frankly, money is the worst possible excuse or reason to do so.
Yes, lines can, and often do get blurred in this business. And yes, it is possible for a lady to fall in love with a client and for them to forge a genuine relationship. However, any exchange of money had better stop if you are venturing into something real.
It is never okay to try and milk a gentleman by letting him believe that there could be something between the two of you, if only she had the opportunity to get to know you a bit better (via paid encounters of course).
I have lost - or I should say ended - numerous 'relationships' over the years because the gent was becomming too attached and wanting, hoping or seeking more than I was willing to openly offer. Sure, I could have abused the situation to ensure greater financial gain, but quite frankly, I like myself, and turning into a money grubbing, conniving bitch would change my opinion of myself.
If a lady likes you and want to get to know you on a more personal level, she should say so, and refuse to see you in a compensated sense.
If she has no real intentions of taking it to another level, she should be honest. Say something along the lines of
"While I value the relationship we have forged within the current circumstances, and I truly do think you are a sweet, charming, fun, intelligent (insert adjective here) man, I am not looking to take this any further than where it currently is. I do truly value you as both a client and an individual but I am not looking for a real relationship. In fact, that is not going to be an option now, or at any point in the future. I am happy to keep the arrangement as it is now, and I understand if you feel parting ways is the best option. However, I feel it is best to be upfront with the fact that there is no potential for this progressing beyond an arrangement of sorts, and ensure that you are on the same page as I. I would never want to mislead you or play with your heart, and while it may sting to hear these words, it is a much better to ensure you know where we stand from the beginning so that you don't get hurt or feel used in any way."
I've had to say that one way too many times, and sure, I could have secured numerous additional bookings and trips with these gents, but it would have been wrong ethically.
I have also gone the other route and found a phenominal parter via the biz. We had a few compensated dates, and then moved beyond that into a very real, open an honest relationship.
I also have 2 very good friends who were clients at one time and are now (and have been for several years) just friends. We talk, hang out and do things real friends do. Time is never compensated, and nothing remotly sexual is ever offered or implied. I would also never see any of then again as a client, since that would ruin the friendship.
I strongly believe that honesty is the best policy. Whether it is a 'real' relationship, or a business one. As long as everybody knows where the other stands, damage control is done, and nobody really gets hurt. That is what this is supposed to be about. Having fun. Not being malicious and using people.