Quoting Steve1989 here: Nice On the other hand I agree with @gda19 though I don't think he's got an option now, I guess they will fuck now something and then her fianceé will appear out of the blue (Ozu's sister called her I suppose), then some drama, and idk.
@Elki I thought about that, but やる is just an informal way of referring to having sex. Plus he's a guy, and I felt that saying "fuck" would be a natural word to use when the possiblity of it is looming down on him faster and faster. Do you know what I mean?
But, i'll take your feedback into consideration and may change it. It's good to get another person's perspective.
やる translates to "do", so "Do I want to do her" should work. "Doing someone" at least used to mean having sex, even if the kids nowadays don't use it. (I have my Grumpy old man card here, somewhere, if I can find it...)
@SveNo やる is one of those words where it can mean slightly different things in lots of situations. In this case, it is an informal, I would say, vulgar way to refer to having sex. I have used "do her" in the past with this word, but I ultimately chose fuck in this case as I felt saying "fuck her" as it seemed to me as being a more frank and direct question to oneself when the chance of it happening is running at you like a freight train.