i know im going against the stream here but he should have killed her
because she is the only charackter capable of directly connecting him with the hero party...
also she is so damn guile able they will probably feed her some bs story and use her to kill off the damn town...
reception girl may know of him too but she can't directly go to the "hero" and betray him
and at least she has the brains to think that since he left the capital way before the demon lord incident he might not be connected to it...
all in all reception girl is a far lower risk compared to that useless gangho low intelligence tsundere...
to be precise the moment she leaves the vicinity of the town would be the moment i kill her