Can I just say "majesty" here? Why should he put "your"?
Native speaker’s answer
Rebecca
Majesty comes from the adjective majestic. The word majesty always refers to something, a concept, a trait that was attributed to someone — much like highness, honour, and excellence. So "your majesty" means "you who are majestic". When you're using the phrase you are describing the quality of the person you're talking to, in this case, the king.