Like what previous comment said, this story is not focused on romance. The romance is just really really small part of side dish. The MC is really...really dense to her own feeling and kind of naive. And ML, well he has some difficulty regarding to his feeling.
In later chapter, the dance part, where ML's father ask Nunnaly to investigate regarding ML's true feeling about the princess as his fiance, he replied to Nunnaly about some law. And I think the law (or rather the background of said law) is the hint about his real feeling.
And about how he is really 'mean' to MC, nah he got a good reason to his behaviour (and it is NOT about how male want to get attention from his crush). If you looked closely at his behaviour, there is some turning point to when he is kind of indifferent to become 'antagonistic' to MC. (and it is later revealed why he did so to MC).
And ML,beside their rivalry, is actually can be protective to MC and helpful to MC (he actually give a hint to how to do some magic that MC find it hard to do). And even until the end, he do what is really helpful to MC. (he really know her so well)