[Merlin still lives -- that is proof enough of that.]
To be lied to by someone you thought you could always trust... it hurts. But that he told you, in the end, and that you were able to look past it, not let that overshadow everything he's done for you [as he must have, as his servant, as someone who possesses such power]... he's very lucky, Your Grace, to have the friendship of someone as honourable as you.
But... you're lucky, too. He must be very loyal to you. [To stay as a servant, even here, in a place where you could be... anything.]