Whoa, that's illegal. She's supposed to brood about things for at least 20 chapters and not tell him how she feels, to make as much miscommunication drama as possible.
So far only some elements was same, like how her sister fake illness and she became the fiancé and improved his health and appearance.
in the novel her sister was not a villain or bully her. Her sister fall in love with the guy that suppose to be her fiancé so she just try to switch with her. They’re pretty much normal sibling. There’s couples other girls as villains