both heroine and villainess are reincarnated people. while the heroine tryes to follow the original story, giving her happy ending for granted, she loses sight of what's actually happening around her; in the meantime, the villainess acts in her best behaviours, ending up gaining the affection of every "capture target" willingly (or, in this case, unwillingly it'd seem), with the result of reversing what should have been the "original story line".
now even before the main story was over, the ex-villainess realized all those guys who since they were kidswould swarm around her kept her from befrending anybody esle so now she is trying to fix that by driving them away... and that's it. let's see what else we're going to get
P.S.: don't you guys think that Sara girl is also reincarnated? she kinda seem like the she knew "if you get involved with this broken engagement, you'll become the king's venting companion"