i played the game and i don't think she is actually a prostitute..
during the scene where you can have sex with her as a reward, if you choose no and hug/ or kiss her (i don't remember), she alluded to not having sex, or it having been a long time.
i think it's more of a geisha vibe with her.
like paid companion/ friend/ girlfriend with no sex. i believe she was abused in the past and developed trauma from it.
also don't understand why everyone wants to have every girl, if you don't like her, don't get her.