Still, in this diary, I'm not sure how much is fact and how much is delusion.
Oh, it is 1000% pure delusion, lady, like holy shit. I mean, sending the letters and the prince hiding them? Yeah, those may certainly be facts, but the delusions pretty much just overwrite any bit of fact in there.
I would call her seriously cray-cray, but the FMC here has also shown some eccentric sides to her with how she receives the yandere knight's love, making me wonder if the prince is the only sane one in this series, which you really do not see a lot of in mangas.