I think she was framed by the emperor, and it the brink of anxiety her father left her alone in the room(probably to take care of thing with the empower) she thought she was abandoned by her father, so she killed herself.
Well, some of what you said is right, but here are some things that you said are wrong.
The emperor didn't really frame her it was her ex, he said something like, "YOU WERE JEALOUS THAT I CHOOSE THE PRINCESS (forgot her name lol) OVER YOU, THAT'S WHY YOU POISONED HER!" And since she has a bad rep in society, no one sided with her and everyone believed that she poisoned the princess. THEN the emperor thought this was a good time to bring down the Duke's power and so told her to be brought to the prison or the dungeon or something like that.
Her father said he would bring her to a room where there were rumors that when someone goes into that room they never come out. After he brought her there before she went inside that room he gave her a knife. She didn't know what that was really for so she thought her father had abandoned her.
The knights were gonna question her why she poisoned the princess, but Max came and said he would question her, he also said something about cutting off limbs (yes our FL heard all of this). So when Max came into the room she thought he was here to kill her and she didn't want to die in his hands so she stabbed herself with the knife.
(Shorter Summery):
Princess askes for a drink.
FL brings a drink.
The drink was poisoned.
FL's ex accused her of poisoning the princess.
FL's father brings FL to the scary scary room.
FL's father gives her a knife.
Max comes to "question" FL.
FL gets scared and kills herself.
Thank you so much. Now i remember after reading your summary. I've been reading so many isekai webtoons that everything mixed up. Lol
I forgot the beginning. So can someone tell me why she dies in her 1st life. I know she kills herself but why?