Swamped

You recall the first time you dealt with a situation like that. You said "I think it'ssss...", drawing out the 's' just long enough to make him think you might be moving into "suit". For just a moment, he looked relieved, and that's when you said "rank".

You were right, naturally.

So perhaps that's the angle here. Try to fake him out one way and see if he reacts. If he were an assassin, then his group would likely have signals to identify each other, if only to stay out of each others' way. Of course, those signals could be anything. Codewords. A particular style of dress. Possibly even a secret handshake.

But maybe you don't need the specifics. You know for a fact there are former assassins in the Marshguards. And you also know that the other Marshguards tend to find them unsettling.

So perhaps you just need to look like you might be an assassin, for just a moment. See if that gets a reaction.

But how can you do that?