He knows what sarcasm is; his parents both have a streak of that human affectation running through their veins and is something Sesshoumaru tries to avoid.

Not considering him a threat at any time is a mistake many people make, and they soon learn the error of their ways. This woman, however, is not using that lapse in judgement as a means to attack him, so she will remain safe as long as she does so.

"That is not a common belief of the humans I am acquainted with."