The Villainess doesn't care about the prince. She didn't even care who took him (the reason she doesn't recognize the girl). She wanted to stop being the prince's fiancee.
The fiancee of her brother doesn't love him. She likes messing around with him, but there is no love. He is her toy.
The knight was put far from the castle because she was too dangerous. At the same time, she is full yandere.
None of the 3 girls are righteous. All 3 are bad. You have 2 sadists (one physically, the other mentally) (A missing scene from the novel: the brother asks to the 2 girls about a vague memory of him drowning in a lake while a girl launched rock. He asked which one was launching. The girls answer that his memory is wrong: there were both her. The villainess launched the rocks while the fiancee abused him verbally); and one crazy. 2 of them show no love and treat their fiances like toys, the last one impose her love.