All this talk of whether Iseul and Theo are mutually bearding reminds me of one of my favourite manga Ebine Yamaji's Love My Life... The main character, Ichiko, agonizes about coming out to her father. (Her mother's been dead for years.) After meeting her girlfriend, her father's reaction was...
'Oh, that makes sense. I'm gay, and so was your mother.'
Ichiko's reaction was something along the lines of 'D:'.
I can rather imagine that Sara's reaction being similar.
(Though, granted with even more reason than Ichiko had, since neither of Ichiko's parents ever went on a homophobic rant at her.)