
That’s actually something I was just doing research on a few minutes ago and all my searches led to it saying that it was perfectly normal back then (plus they either may not be related at all due to like cheating (doubtful) or you have to remember they are only half siblings. Either way I do think it’s super cute how much he cares for her and honestly I wouldn’t have an issue looking over the incest given the time period and the relationship by blood being only half. It’s cute (▰˘◡˘▰)

Yup! This is v cute and interesting rn and I think the only thing that would stop me from reading this is if it got ridiculous or boring plot wise ٩(๑❛ᴗ❛๑)۶
I don't really have anything against their relationship tbh (or any other fictional pseudo-/incestual relationships for the matter). Especially with how the supposedly ml did not really saw mc as her sister or anything so this is pretty pretty tame and easier to swallow for those who may be icky with the subject. I just wish there won't be any "but he's my brother" drama ╮( ̄▽ ̄)╭ but I think this won't happen coz of mc's character.
And yeah, I think inbreeding was historically accepted especially to royal dynasties coz power.
Gonna assume that the sixth prince is the ml of the story? Boy got no business blushing for his supposedly sister. Then again, pseudo-incest seems fine with them. The third princess did tease the fl if she liked the 1st(?) prince enough to marry him.