Rozaline is an interesting character, at least when compared to most generic evil-ladies-in-waiting in this sort of manhwa anyway. She's smart enough to know who to ally with given her situation and wily enough betray people at the drop of a hat. This makes it quite hard to tell who she will ultimately side with.
Is she currently scheming behind the princesses back or is she luring the other ladies into a trap? She has no love for the princess, but once she realises the princess is not as inelegant or uneducated as she thinks there may be some worth to having the princess as a master.
EDIT: Nevermind, hadn't finished the chapter. If they side with Dionna, they'll obviously be going down at some point, need to wait and see.