The translation is weird I admit.
Clarification:
The male lead thinks he has brainwashed Duroa. He calls her Valrose to maintain it, but if he called her Duroa it would strengthen it and she would become a puppet and break her mind. Because he always ordered her to come back no matter what hell he put her through.
ML doesn't know that Duroa is not under his brainwashing and the reason she kept coming back when he 'ordered' was to cultivate a friendship with him so he would be attached enough not to kill her.
ML is in love with Duroa, but the misunderstanding that hurt her are things he has to do to protect himself or her. (Like not drinking the tea she made for him.)
Alice and Aaron are in love with each other, but Alice doesn't recognize Aaron (weird magic disguise). The translation is a little unclear and I can't tell if Aaron is just so invested in Alice Momentum (which was Alice's identity in the story) and can't bear to fall in love with someone who looks like her, or if he knows that his Alice and limarond are the same.
Duroa wanted ML to be her friend. She thought perhaps if he grew fond of her, she'd escape death. She also cultivated a friendship with Alice to escape death too. She figured that Alice and ML would fall for each other... and so she got engaged to the first person who seemed interested, not knowing that Aaron was the male lead of the original story and that Alice only fell for ML because she thought he could have been Aaron...
Wow. After explaining all of this... yeah its a mess... but damnit I love it.

Honestly everyone except valrose is kinda trashy.
The male lead...he's a deranged maniac. There's literally not one good thing I can think about him. His looks aren't even all that's either
The fiance:....look, he's not "bad", per say, but he's too damn indecisive and kinda just...idk, but he's gonna end up hurting everyone- especially if he doesn't hurry and make up his damn mind
The heroine: bruh, she stole both of valroses man's. She thought that valrose liked the Duke but got engaged to him, and is also attracted to the blond dude even though she knows that he's engaged to valrose ajdkjanafjdjd sorry but everythings so messed up here
Also, valrose.
Did you, or did you not like the Duke that way?!?!
Cause she kept on saying how she had un unrequited love for him while he kept ignoring her but she also always denies having a crush on him like???? Pick a side already???(it might just be bad translation or me running on 1 and a half hours of sleep tho)
ALSO also, did she get brain washed then?
Cause she said that she was being forced and didn't know why she went but she always appeared to be in control of herself and not brain-dead like the others under his spell.
Man I'm confused