Admittedly, he hadn’t really planned his route of action terribly well, but he’s counting on his incredible streak of luck to pull him through. Simply put, he has a message to deliver to a king, one crafted in the form of a double-edged sword.
It’s a secret message, so he conceals it underneath his clothes and goes to the king with the truth. Well, a half-truth, but those are always easier to tell than complete lies. He can admit he’s not the most creative or imaginative of people, but he has his luck and he has his skills, so he’s going to make the most of what he has than what he doesn’t.
So he pretends to be a messenger, and when the message literally sinks in to its receiver, he sneaks away, and wonders if it counts as murder if he believed in his own lies.