In other words, does a man have to disclose his intentions before hooking up with a girl if they met in a place where it is assumed that people meet to hookup except she may be ignorant of that and has in mind a long-term commitment.
Rambam Laws of Marriage 1:1 and 1:4 describe the parameters for non-Jews.
א קודם מתן תורה, היה אדם פוגע אישה בשוק--אם רצה הוא והיא לישא אותה--מכניסה לביתו ובועלה בינו לבין עצמו, ותהיה לו לאישה. ...
ד קודם מתן תורה, היה אדם פוגע אישה בשוק--אם רצה הוא והיא--נותן לה שכרה, ובועל אותה על אם הדרך והולך לו; וזו היא הנקראת קדשה.
Before the Torah was given, a man could meet a woman in the street; if he and she agreed, then she'd go home with him, they'd have relations, and they'd be a married couple. ...
Before the Torah was given, a man could meet a woman in the street; if he and she agreed, he could pay her, "hook up" on the spot, and then part ways.
So there is "both sides agree on a long-term relationship." There is "both sides agree this is not at all about a relationship." I am not seeing "one side is only consenting because they assume it's a long-term relationship when the other side thinks it's not."