It was already a theory, but imo the flashback of the guy hanging himself is basically confirmation that Sooha is the girl Joonhyuk's father wants him to marry.
As for whether or not Doh loves him? That is honestly a very hard question. Others will immediately say yes, but I think it's not that simple here. Doh liked Taesoo in the beginning, too, but her life was tough so she took it out on him. So I think that the money is definitely a part of it, but I think overall she genuinely likes Joonhyuk. Or thinks she does.
> "Others will immediately say yes"
As in she doesn't really love him
Could the friend of Joonhyuk's dad who loaned him money and died be Sooha's dad??? Omg oh shit. (just a Theory I know it's too damn early for theories) but imagine the drama lol