
Ok, this is all such a weird plot and character development.. why is she so harsh with the og ml from the get go? it seems like it could be solved with a conversation? “Dude I’m your friend, but you have a fiancé and I have a boyfriend. Let’s set some healthy boundaries?” Before a “I hate you, get out of my site you bastard”

She has told him this houndrids of times, yet he keeps over stepping. This has increased the rumors about her, leading to his female fan's causing actual harm to her home and family. And his fiance who is active in social gatherings to hate on FL.
His female fan's from school days were higher in statuse than mc and used their power to hurt her by fx. paying someone to poison all of ther estates horses leading to them becomming poor (they were famous for beeding top notch horses).
Their family carriage was sabotaged more than onece leading to many injuries and accidents + her general poublic persona being slanders because he clings to her yet says "shes my childhood friend" leading eveyone to think she as the lower status woman was seducing and clinging to him.
These are just a few of the things his fans have done to her to, she says herself she cant be botherd to list them all because it would take ages.
She became harsh because he was causing everyone trouble and in the end because he ignored what she had to say she started to see him as a nusance and hate him.

It deviated from the novel a bit :p here Kael got quite sick again, and felt guilty that Diana talking to him still made him happy..

You're getting it wrong. Idk bout the novel but here, it's not that he's happy diana talked to him and he felt guilty cause of it.
He felt guilty because he felt no emotions at all when diana talked to him.
He's saying something along "I feel guilty cause I don't feel any sadness or any feelings when she talked to me. After all, I used to love her with all my heart".
He's saying he's feeling rather indifferent to her talking to him. Which in turns make him feel guilty

I’m not getting it wrong cause I’m precisely comparing both.. That’s why I say it’s different from the novel. In the novel he feels bad that it felt “nice” taking to Diana and feels foolish about it. He still highlights that it affects him (to the point of getting sick afterwards) which is the opposite here, it was a clean cut. Although he does reassure Hess has no plans of ever leaving her, and cares for Hess :)

Let me dissect what was said for you cause I can assure you that my reading comprehension is completely fine and since the op tried to tell you the same thing as me and they wrote it (the original comment) I’m sure they know what they meant.
“It deviated from the novel a bit here” implying that the manwha has decided to not follow the novel precisely.
As for the rest of their sentence they are referring to what happened in the NOVEL “Kael got quite sick again and felt guilt that Diana talking to him still made him happy”
These are things that happened in the novel, him being happy talking to Diana and then feeling sick from guilt because he felt happy. (If you read the novel of have been reading the comments you might have seen this before)
Just saying

Let me dissect what was said for you cause I can assure you that my reading comprehension is completely fine and since the op tried to tell you the same thing as me and they wrote it (the original comment) I’m sure they know what they meant.
“It deviated from the novel a bit here” implying that the manwha has decided to not follow the novel precisely.
As for the rest of their sentence they are referring to what happened in the NOVEL “Kael got quite sick again and felt guilt that Diana talking to him still made him happy”
These are things that happened in the novel, him being happy talking to Diana and then feeling sick from guilt because he felt happy. (If you read the novel of have been reading the comments you might have seen this before)
Just saying
She needed to act quick.. why gather evidence at this point? Just tell the father he’s cheating and raping her, tell about the conversation heard and that the marriage is not gonna happen regardless. Then if father still decides not to believe her and to leave the company to him there is not much she can do now is there? Or maybe then decide to gather evidence? But that would be her best gamble. If he dies and actually leaves the company to him, well then, too slow.