Met a girl, she has a boyfriend, so what to do?
How much time has passed? A couple months? If so, go ahead and ask her for advice on becoming a dealer. She’ll bring up the boyfriend again if you make small talk, if she still has one. If she doesn’t, go ahead and ask her out. Don’t ever let her know that she’s the subject of a yearlong crush (well, maybe after you marry her). If it’s just a couple of weeks, well, be cordial, but don’t pursue her.
Deliberately trying to interfere in someone else’s relationship–whether it’s effective or not–is deeply morally suspect, not to mention deeply disrespectful. There you go again with the moralizing. Maybe she’s trapped in a crumby relationship and he can be her ticket out? Maybe her boyfriend has five other secret girlfriends and a dead body under the bed? The point is we don’t know, and giving her an opportunity to dump him for a shining prince might turn out to be the best thing that’s ever happened to her. But that’s all down the road. Please remember all he did was ask her out for a coffee, and asking her a few questions about dealing with a nefarious intent of making her fall in love with you is not “strictly off limits” at all.
I say go for it. Try again. If this happened a year ago, she’s not going to think you’re creepy. I’d find it creepy. Especially if it’s preceded with a “I just moved to town to be a casino dealer just like you!” You’d be surprised how often waitresses/those in customer interaction do remember customers and patrons once you see their face again or hear them speak again. but this time make sure that you don’t get turned down. There’s a fine often-crossed line between being charming and persistent and being slapped with a restraining order/getting kicked out of the casino/making a bad name for yourself in town/getting punchasized in the face by her boyfriend.