本当にそっちか

23:59 Mar 26, 2016 

Thank you very much, it really helped! ^^

16:52 Mar 24, 2016 

In Japan, they define themselves as M (Masochist) and S (Sado). It's not only related to sex but also to character. For example, a girl who likes to be treated cold by his boyfriend would be a M. And his boyfriend a S person.
When he hits her, and she ask for more, his response 本当にそっちか, makes reference to his surprising that she is a M person/girl. (She liked being hit)

Now well, giving a translation for English is complicated.
I'll go for something like: "You liked that?!", "You are that kind of person?!","You like those kind of things?!" or something similar.

Hope it helps :)

15:23 Mar 24, 2016 

depends on the context
前後のやりとりがもう少しわからないと答えようがない