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.
Is it genevat daat for a Noachide to have relations with a gentile woman without commitment if you met her in a place where people normally hookup?
1I used a slang term that figuratively means "an obnoxious, offensive, or disgusting person", without realizing just how graphic the literal meaning was. So I will retry: don't be an obnoxious/offensive/disgusting person. If you have reason to believe someone is entering any kind of agreement with you under false pretense, let them know; don't say "oh they should have known better given the circumstances."– ShalomAug 10, 2021 at 23:57
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."
The Rambam reads: אם רצה הוא והיא לישא אותה - He and she decided to marry (not just that they agreed to have relations). For a Noahide, when/how is the threshold crossed from a non-binding sexual fling, to becoming a binding marriage? Aug 10, 2021 at 13:24
@IsraelReader read any general-society advice column these days; it seems everyone is struggling with the issue of at what point are strings attached and how serious does that make it! If I had to venture a guess, there's language regarding a shifcha about "when everyone knows she's his", so I'd imagine the same thing. "When they make it known to most folks that they are a couple and exclusively so." (Or just keep checking the status from HaGaon Rabenu Facebook haNavi.)– ShalomAug 13, 2021 at 1:55