The romance is quite good IMO but it's not the core of the action. It's on the star-crossed side because she's a princess, if a princess behind the 8-ball politically, while he's not only a servant but some kind of blond barbarian orphan. She's going to need to either win the political game resoundingly or quit and run away if she wants to be with him.
The original tragedy is that her mother was a victim of wife politics. She bore a daughter, but this nasty bitch gave the queen a son and used the leverage to push her aside further and further and eventually do her in, leaving our heroine without any significant support at court and with a stepmother gunning for her. Since then she has been used as a political chess piece between the four kingdoms, but gradually learning to be a player in her own right.
However, some bad stuff has happened since the original tragedy. She has not had smooth sailing and more than one significant sympathetic character has died.