I'm in the midst of denying reality in terms of how this manhwa ends... Like it's so good!...

i really don't understand how someone can like this horrible sexist story

Where do you see more sexism in this story?
I do'nt say that there is not, only that I wonder what bothers you, since the plot that I see is about a girl raised in a pratiarcal and sexist society where she is used and cruelly tortured by the man she loves (Kill the prince), and has a second chance and tries to live a life independent of him.
(I would likevery much that she achieve that goal)
I see the horrible and sexist points, as it depends so much on the opinion of the majority of men have about her(Including their father, and supposedly he shouldn't count as "romanceable man" XD), and that she needs a constant help and emotional therapy... constantly (It feels like they literally are continually telling her that she can't live independently without a man), but otherwise I don't see it horribly sexist, because technically she is trying to overcome that and become stronger and independent (And she works hard).
That's why I would like to know from your point of view more detailed, if possible.

I don't think the story itself is particularly sexist, it's just the setting. There's a difference between that, the author isn't promoting anything sexist, as far as I can tell o:

this is (in my opinion) a sexist manga because like you said the story is constantly saying that she can't live without men. The author try to tell us that " oh she can fight so she changed and became strong but all of the male character are much more stronger than her because..well she still a woman" these stereotype of how a woman should be fragile, naive, pure, docile and humble are overpresent and I really have enough that women in shoujo particulrary are represented like this, young girls read those and become formatted this way. There is also the fact that this manga encourage women to forgive horrible men for a false idea of love (if it was realistic she would already have beheaded this asshole) this man beat her, torture her, raped her (yes because we can also talk about rape in manga and this one was definitely a rape), you mustn't even think about forgive some trash like him whatever is his shitty excuse (sorry for the language ^^'). I really can't stand this feeling of domination and being a possession of some men, look at how the two male best friends talk too each other "don't touch her she's mine!"" at first you can see this as a romantic sentence (and that's how the author want you to see it) but what we can also understand is that the girl is perceive by those idiot like some object that they can take ownership whenever they want to and of course without her consent. Also you said that she is trying to become independent and yes she is but she will always be dependent of a man , she will forgive the trash and will only think about love (because of course that's all it matters to girls) instead of thinking of how to become really independent from men. Sorry for the long text I hope that I ansered correctly to your questions

First, thank you for answering me in an honest and detailed way, that your message has been long has made me appreciate it even more, thank you (=・ω・=).
Second, unfortunately you HAVE ALL THE REASON (╯°Д °)╯╧╧, and I share your opinion.
Third, after your message, I read other comments that contained spoilers, and that made me investigate the ending, and you guessed completely about the ending (He remarries the fucking prince and forgives him (╬￣皿￣)凸).
Fourth, I think this story shows more the essence of a toxic relationship where you let your partner do everything, and you forgive her, since that is "true love" ┑(￣Д ￣)┍ (At least she expected the prince to kneel before the girl to beg her forgiveness and love, but not even that (╬￣皿￣)凸 (╬￣皿￣)凸).
Fifth, what interested me about this story was the prince, and that of a weak protagonist overcoming her weaknesses and becoming strong, but you were right, the story is predictable and trash （￣へ￣）.
I thank you for saving my time, I will use it to read worthwhile stories(≧∀≦).
I hope that you also have luck in finding a better story than this one (●'◡'●)ﾉ .

You're welcome! good luck to you too (i really enjoyed talking with you ^^)