The problem with this is usually being seen as a lunatic and whatnot. Remember, it's always medieval settings, and back then if you claimed some sorta powers or knowledge or aid by the gods, people would have either killed, imprisoned or burned you, among other options.
In general it's actually more clever to keep quiet and use your knowledge. Especially since, in political settings with power struggles at every corner, you could end up being kidnapped and imprisoned so people can use you to gather information under torture and such. So yeah, keeping quiet is the best option. Even if you trust someone, they can turn on you and view you as a lunatic or saying things could alter the flow of what you know into a VERY bad direction.
Okay, I'm currently at the latest chapter that is chapt 77 andddd if ABEL DIES imma drop this story. Plus, I think this far on this so-called novel of hers, she should've just come clean to the ML. But that's just my opinion. She already altered the story soo much so what's the problem in confessing? (Confessing that she's the author not confessing her love cause she's done that already.) The dude is head over heels for you, my girl. Can't you see? SMH ヽ(`Д´)ﾉ