Considering the power dynamic--a prince v. a count's daughter, I can see why the FMC caved. Normally, it's a slow process over the course of months where Joseph would suggest another thing for her to change to make her more attractive to him. For the FMC to explain it all at one go was a bit much and seemed far too much. And Yuri is just incredibly tactless. Right now, I'm not really invested in the FMC, but I dislike Yuri and hate Joseph.