[Looking down at himself, as if that will possibly reveal his state of demonicness.]

...Well! For what little it's worth, I don't feel possessed? Though that's exactly what a demon would say. You could check my clothes for poisons and come with me when I deliver things to make sure I don't stop anywhere to add anything on the way? Mm, but I also feel like I wouldn't go for something like that if I were a demon. It'd put suspicion down to one of the two of us - fifty-fifty aren't good odds at all!