[ that make things clearer, khun nods and takes a sip of his beer. ]

That's similar to how the King treats his princesses. Princesses are chosen from young women, independent of their previous social standing, based on the beauty, potential, skills, and a whole host of other criteria. When they become a princess they become property of the King and are forbidden from having romantic or bodily ties to anyone.

Not that they ever consummate their relationship with the King, they're just show pieces.