Well the story is a lot complicated than that and u'll see the reason for all this in the end
(it might be a little bit spoiler)
I understand you so much!But..
I read the novel a bit before this became manhwa. I found all of the situation are ridiculously making new misunderstandings, even in the second life (well, not a really serious matter, actually cute, but still irritating XD)
My point is you are right about the lack of communication, but you will see later on that her father actually did his best. I did pointed my finger on him,but Cherry is right. I predict that everything that his father did even before the second chance had their own reasons.So lets be patient and wait !!!
OK, I understand that the dad is trying to keep his one and only daughter safe from the Emporer, but he could have at least in the end told her WTF was going on before she killed herself so that there wouldn't be any sort of misunderstandings in the first place before she slipped into the past/also reincarnated to that world. Plus the fact that he is finally trying to get close with his daughter after the reincarnation kinda pisses me off, LIKE OH YOU ARE FINALLY TRYING TO ACT LIKE A FATHER AFTER IGNORING HER FOR 18 YEARS. Alright cool, but there will be more misunderstanding if you don't tell her shit especially since she is an adult now and knows what is sort of going on, but only because she remembers it from the past.