It was just someone who read the novel. She/he comment it under a picture but I can’t find it anymore sry. I also found some spoiler on novel updates https://forum.novelupdates.com/threads/the-way-that-knight-lives-as-a-lady.115828/page-2
Some spoilers were really hard to understand. But in the end she will married the ML.
Sry I don’t know much either https://m.blog.naver.com/fkdla2016/220947117343
They are some raw pictures from the novel
https://forum.novelupdates.com/threads/the-way-that-knight-lives-as-a-lady.115828/
On this there is some spoiler about the the character, it was kinda hart to understand but maybe it will helps you a little. I just scroll down a little. The Name of the comment person is: -NEAR- -> click on Spoiler: Charakters (she also post the link with the illustrations) :)

I read on Instagram:the king/kingdom that she is fighting for is actually corrupt and when they about to lose, the king wanted to put the blame on her. She also killed a lot of innocent people, which she doesn’t know. Khalid founded out and he could not tell her because he loves her and is afraid that it would mentally break her. So he killed her that she can remain as noble a knight.