Because you keep circling back to the ring I want to hash this out... Am I remembering incorrectly or did Kohaku fixate on MC "before" putting his ring on? She didn't tell him she's a nympho at that point but it seemed obvious she was already pretty into him. Yes, all that can be re-written but it kind of destroys the theory that the rings were originally intended for that.
I'm sorry if there was a misunderstanding, what I say is pure hypothesis or at least how I understood the beginning of the game, it should be clarified that of course I could be wrong in my thinking, the only one who knows this well is the creator of the game.
What I remember and what led me to this line of thought is that at the beginning the seller tells him that if he wears that ring (which he is trying to sell) many women will come to him and even lick his ass, but he is not talking about simple bitches but nymphomaniacs, even so Jimmy leaves without being interested, so the seller tells him to give him another ring as a gift, one of love/erotic, although it says love/erotic we don't know if the second ring really has the same function from the first, is it a simple ring or does it have another power or curse, we just know that Kohaku uses it to think that she is in a relationship with Jimmy.
The first ring attracts nympho whores like Kohaku, the ring is cursed therefore the wearer cannot take it off (I suppose it can only be taken off after death or their finger is cut off), and about the curse This could be that the bearer attracted very beautiful girls to his side, falling in love with them without knowing that they are nymphomaniacs and breaking his heart to see how they really are, as time passed the voice passed from bearer to bearer until many knew what the ring was like and they preferred to avoid that problem, that's why they sell it so cheap, I don't know if that's the same fate that awaits Jimmy taking care of children other than his own while Kohako goes to nights out with friends like Yarizo, breaking it in the process.
The most curious thing is that the boys from the beginning that annoy Kohako, I don't know if they end up dead or just fainted, but maybe Kohaku lacked being horny to accept his proposals or he was getting turned on by them, giving in in the process or simply if they bothered him, I wish I could see it from Kohaku's perspective, after that as I mentioned earlier Kohaku could simply thank Jimmy and leave as he thanks Leon when saving them from Goliath, we must keep in mind that the ring is the trigger of the story by bringing together the nymphomaniac heroine, the true protagonist while Jimmy is an extra from the player's point of view, so she invites Jimmy to the Unicorn Dancing, believing that she feels something for him without knowing that it is because of the ring.
It is more remembering well the drunk who spoke with them on the bridge, he is right with Kohaku's dirty attitudes, the "pure" attitude from the beginning that Kohaku has towards Jimmy at the beginning is so that he does not think badly of her because he is afraid of driving him away by letting him know that she is a simple whore because she took the vision of her ideal master and implemented them in Jimmy without even knowing him thanks to the ring because otherwise it would not make sense for her to fall in love with him so quickly, that is why I reiterate that all this is thanks to the ring, a false feeling created by him by fulfilling his goal of attracting nymphomaniacs.
(I hope to see the drunk on the bridge and the two adventurers from the guild and the fakers that Goliath beat later in scenes with Kohaku, all of that would sink Jimmy more, of course as long as the last ones are really alive)
After this they go to Jimmy's room and before the facts she presents herself to him as he is, she confesses, saying that "she thinks she loves him" she calls him "destiny" nothing better described because that is the destiny of the ring, no Jimmy's
As Kohaku says, she was looking for a master and only thought of Jimmy as a candidate thanks to the curse, even Kohaku feels sorry for saying it so open to Jimmy that when he returns to the room he thinks of leaving out of shame.
What I don't remember clearly is if Jimmy tells León that the Priest is a whore, or if he leaves it up to one's interpretation
I reiterate this is the way I interpreted and understood the beginning by sharing it with you, you don't have to think like me, nor do I say that it is 100% like that, what the author meant or did not mean, I simply say what I understood by playing the intro.