Idk if declaring someone as your future husband in your head is sane but I guess she would come off as the friendliest from the brief time here (without looks into their heads).
Hinata seems the most sane with all context, Kanaria is about Sou's family level, and Miku seems like she's gonna be insanely obsessed with smells for a while.
In a world with one boy every 39 girls, if you are a girl and you find a boy you really like it makes sense to go all in and try to marry him.
Literally 97.4% of the girls will NOT be able to marry, and will end up being alone. Literally 1 girl in 39 will be able to marry.
So in that situation, I'd say it's pretty normal to be super invested if you find a boy you like. And being horny is not an abnormal thing so... I thought she might be sane.
Alas, this chapter showed that she does have... questionable tastes. Still better than the smell crazy girl probably....
As for Hinata, I will admit that my initial distrust comes from the fact that she seemed too relaxed about the whole thing, so maybe she would turn out to be some sort of freak. TIme will tell, but at this chapter I agree with you that she might be the most sane.