@Sa_Ku_Ra Yeah, that's a wierd one. I though its just that successors can't be married out of the family. But she's talking about something else entirely.
Can it be that the writer meant 'playmate' previously, but when the chapter got translated they perceived it as engagement? Though there’s a loophole here as well, since Aegis mentioned marriage and dating multiple times afterwards. It seemed possible for Aegis & Tilly to get together in ch.28
@Sa_Ku_Ra as much as I remember form the previous chapters the characters actually did not have any powers until I think around 10 years. It was stated in the near beginning chapters that there had not been any magic seen for around 400 years so, the king actually wanted to get them engaged to prove that there is no longer any magic in existence