Every situation and every lady is different.
I have casually dated about a dozen working gals over the years without falling in love. Never bothered me that they were banging dozens of guys a week because it was just meaningless sex and I was in a real relationship anyway.
None of them ever asked for financial help or expensive gifts, we were just friends and I was certainly not after anything more than someone to talk to and share time with.
Mind you I am aware of the types to look out for, those who see money as King and will do and say anything to get you hooked and access to your wallet.
I am currently in a fabulous relationship with a girl I met in the biz a few years ago. I will not go in to details other than to say we tell each other absolutely everything about ourselves and our lives and spend a large part of our free time together. Yes I usually pay but she does sometimes and that is no different to any regular relationship I have ever had.
Am I in love, absolutely. Is she? She loves me, but in love .... the jury is out, too complex a question. Am I naive.....hell no. I know we will remain friends whatever happens and to be honest that is enough for me.
She is the reason I have not visited any WL or ML for quite some time and may never again. A truly profound positive influence on my life for all time. Most definitely one in a billion.

So saying I have to agree with a lot of the comments on here. Do not think with your dick. If you are visiting WL/ML for sexual relief then keep it contractual. If you see her outside of her place of work keep that contractual too. If she asks for financial help use your head and logic. Most times it is a major red flag.
The most important thing is what she does for you, what she gives up for you and what she talks to you about.
Does she show an honest interest in you as a person? Does she go out of her way to see you? Does she contact you just to say hello or ask how your day is?
It is the little things that she does and says that matters most.