Just a nagging run of words that wouldn't leave me alone. ENJOY... or don't your choice.
Merlin thinks he's stupid, but that's alright because he thinks Merlin's an idiot.
Merlin thinks he's blind, but he knows Merlin has some sort of perception disorder; nobody, normal or otherwise, could trip over that many things.
Merlin thinks he doesn't know; he does, the magical manservant is just not as stealthy as he thinks.
Merlin thinks he can't be trusted with the secret, and that's alright too; one day Merlin's secret will get him into a lot of trouble and Arthur will have to bail him out, and then Merlin will understand.
Arthur is not stupid, he is neither blind nor ignorant, he is just waiting for Merlin to understand that the complete and unending faith he has in Arthur is mirrored by the complete trust and faith Arthur has in him.
Merlin thinks Arthur makes a terrible prince, Arthur thinks Merlin makes a terrible manservant.
Merlin thinks Arthur will make a brilliant king, Arthur knows Merlin will make an excellent royal advisor; he just has to figure out how to make that ridiculous hat part of the royal advisor uniform first.