I am so in love with this plot. It's so freaking good!!
We are learning so much about what happened before all the things happened.
Spoiler maybe?
I think Psyche was straight up manipulated before she even meet the prince,aka her family made a deal with the prince or something like that. And the reason she was kept in the basement is exactly as you see her, to keep her away from any knowledge and to be naive. (To be easier to manipulate her and make her think he loves her)