It is a Japanese webnovel, where the FL transmigrates into the villainess who is the daughter of duke(or marquis). She loved the dude who was the viscount in the novel so she goes to save him from his death or blackening(I think). He loved the oriFL who went onto marrying a powerful duke. The FL wants to recruit the Viscount into her family's army. I think the oriFL has some leftover feelings for the ML. He even planted daisies(or some white flower) because it was the oriFL's favorite(which he later ruined). The oriFL is a nice(?) person. The oriML becomes interested in the FL. The FL's body owner used to be obsessed with the oriML and would harm all women who went near him. The oriML and oriFL have a contractual relationship. The ML begins to slowly fall for her. They learn to exercise together at the park. The FL's father is a sweet person. That's all I could remember of the novel. If you have anything similar to this as well, please let me know. Thank you very much.