The start was iffy, the villain schemes are pathetic, as someone else already pointed out, it would've been ridiculously easy to check if the "fiancé" thing was a lie, which would also made much more sense, as false claims towards the royal family members easily classify as slander and can be stretched as far as treason, so...it would've been much more effective in destroying a "delusional fool".
(this is also why I can't stand all those storylines where the villainess is like "he's mine" without being anything official, and the Emperor/princes just sitting there instead of taking the bitch to court and ruining her as warning and example for all other fanciful idiots)
I guess the FL is sheltered? Although, how she could be that, when she's obviously been into society enough to know how it works...her not knowing the Emperor is such a stretch...
Also, her having no backup plan when she obviously expected something bad to happen only for there to need saving by the ML is such an insult to everyone's intelligence, that I can't even begin to explain how ridiculous it is.
Same for her reacting like a 12 yo when she's supposedly an old woman on the inside, Jesus I'm not even past my thirties and I would never crumble as badly as her, while I would've definitely reacted like that as a teen. But as an adult woman, bitch I would've laughed in her face and asked her how she could be so sure and whether she had even verified if it was true because - read my first paragraph-.
All in all, this is kind of very silly bordering on terrible 😒