All right, possible explanations: the place isn't actually Lawful Evil, and he feels like he needs to make this unambiguously a quid pro quo of some kind. It's not the Asmodean way to do this; the Asmodean thing to do is exactly how he pleases and if Carissa's able to play for anything she wants from there, good for her, and if not, bad for her. But she can imagine how a place would end up as terrifyingly full of assassins and intrigues as this one and still have some vestigal Neutrality.
She's of course not going to tell him if he's doing it wrong; if she can leverage this into getting something, great.
Separate possible explanation, not incompatible with the first: he likes his girls apparently willing and most people don't have the Bluff to fake it. Do compulsions not work well for that? Charm Person does just fine for most people, is Carissa's understanding, though she personally always had a rule that if she found herself liking or trusting a man she should pretend, indignant, to have made her Will save, and walk away....
Third possible explanation, he's toying with her, in which case she probably wins more points by seeing through it. Damnit, she doesn't want to be ilani here where it's not safe but it's harder if you aren't thinking to make decisions clearly, and that's the mistake she was making all along, right -
Fine. What percentage of people like their girls apparently willing? She has no idea, say it's half, that's not off by a factor of 10. What percentage of people like toying with their prisoners? ...say half again? This is hard to do in a culture you've never come into contact with before. Has she observed anything that's more likely in one world than in the other? The bath points towards 'toying with her', she thinks, maybe 2:1. Something about his expression feels like he's not toying with her; how likely is it he can bluff her? Probably 10:1 that he can; he's an important figure in an imperial palace.
Collect more information, Carissa; when you don't understand reality go out and look at it.