
Why didn’t Mc just tell her brother that the child couldn’t possibly be his bc he never mentioned nor talked about having a lover or anything. Also he basically told her before he lost his memories that he’ll never marry/have kids unless it’s within a political marriage that will benefit him which Mc knew that him saying that implied that he doesn’t have any lovers. Why can’t Mc just tell him or explain that or am I missing something that’s preventing her to do so? I’m still only at ch 31 so maybe I’m missing soemthing ╮( ̄▽ ̄)╭

I feel like he's already aware of this as those are personality traits from even before his arrived at Noart.
So, I think it's less that he believes the lady is totally good and/or truthful. More that if there is a kid and it is his, he'll do what he feels is his duty immediately and halt any questions or self doubt about the situation.
Just my 2 cents

Yeah, I do not recall what chapter it is, but he does say that he must NOT ever doubt the child is his. Even if everyone else does, just the possibility of the child being his means he must never doubt his own child because he would never forgive himself.
It is less about believing the woman, and more about protecting his (possible) child and sticking to his principles.
I also think he might distrust his adult self, and I don't blame him. Imagine being a teenager (full of rage, as the manhwa says ) and you wake up one day, and you are the heir to a fortune and people around you say you are an adult who has his shit together.
He doesn't know who he was, and his sister insisting it is not possible is not going to change that. For him, waiting for the "child" to be born and having others check for the paternity might be the best solution.

So Annette’s body is technically the original body of their daughter right. And the father (sorry I forovot his name) is brothers with the lord of Argo, but the ml is the son of then lord of Argo, then aren’t they technically cousins???? I’m confused, is it just a mistranslation or is some sort of cousin incest? Bc even if they’re still cousins bc mc is using the og daughter’s body, so isn’t it incest? Im confused.. someone explain please?

In the most recent chapter (27), ML's father says "ever since we met" to MC's father. I've been assuming that they'te not biological brothers, but it's more of a close platonic relationship/friendship between them (like the term "brother" is a translation of "hyung"). I could be wrong though, I don't know if there is an age limit to use the term when it comes to social etiquette and I've mostly seen it used by fairly young men (under 30s) in the manhwas I read ( ̄∇ ̄") if anyone is more knowledgeable on this, feel free to reply.

earlier they called him a friend but then another translation team took over, using machine translate i guess which would translate hyung to brother, so the white haired duke is shakol’s older friend. so they’re not related at all
i think she is the real daughter bc she went back in time and was experimented on and still got the curse text on her even in the present life and! the father said that the real daughter had his eye color - purple. so she couldn’t be her- unless she got experimented on-
can’t 100% trust the translation but i think she’s the real deal
we haven’t seen how her face/eye color looked like in her past life

[Spoiler warning]
The og comment and the reply above it already discussed this, these are spoilers that have been shared (at least in the comments, likely somewhere in the reviews too). The body MC is currently using IS the biological daughter, and the memories of the past life belong to the body. The soul itself is not the original daughter's - the switch happened between the reincarnation, and I think the eye colour change is due to the experimentation (could be wrong on this, someone did say the reason somewhere but I forget what it was exactly). MC's soul is a transmigrator who knew of the og novel (although she has yet to realise this).
Eventually we will get to meet the og daughter, she'll have/get a new body, she'll also later be adopted into the family and they will become a happy family together.
This is according to spoilers given by others, I haven't read the novel.

All of the characters r so dumb. That bitch could’ve easily ended everything if she just reported the kid, but no. This is stupid too why are all the characters so fucking dependent and why are they not doing anything to solve the problem like idiots they’re literally blaming each other except the culprit?????? The plot armor is crazy wtf
Why was this axed.. (╯°Д °)╯╧╧ I really liked the story, but the pace jsut kept on going faster and faster… this should’ve been at least 200 chapters ╥﹏╥ I wouldn’t have minded reading it for that long