It's not easy to tell at all! The good ones who are good at their trade don't dress overtly sexual, and they seem like normal women. I was being worked over once when I was 18, and I didn't even know it. I was in some bar that my friend's father owned and this beautiful, young woman started talking to me, smiling, giggling, and touching me alot. I figured, "she wants it." Later in the evening, she scribbled on a napkin "$$$." I thought to myself, "WTF?" , and I gave her a look that showed confusion. She smiled and whispered, "300 hundred for the hour." My jaw dropped, and I explained to her I didn't know she was working me over. She apologized profusely, and she was genuinely embarrassed. She got up, and I didn't see her again all night (or ever). I didn't call her on her attempt as I was completely dumbfounded. I would've never have guessed.
Moreover, a couple of guys at work that I know brung their "dates" out for drinks. I thought they were their actual dates (although, they seemed completely out of their league). They were knowledgable, educated, and warm, friendly gals. Only later did I find out they were escorts.
I think I respect hookers (upscale ones, at least) more than I do the average wh0re. At least they are honest and up front about what they do. I disagree that they are picky for submissive men that have a tendency to "settle down." They are generally more picky for men with money! In general, from what I hear from the bozos at my job is that they are not out to hurt you or make you fall in love with them. They want you to have a good time, and they want to get paid. It is a business transaction to them. They provide good service in hopes that you'll come back for more.
It's a much better deal, I think, then going out with an apparent "good girl," and later finding out that she's had trains run on her, or got f*cked by someone in the @ss while you were away on vacation, or some sh!t like that.
TOOTLES™