Place it right after the accusation in your edit, as the reply that turns the doubt back on the accuser, then follow it with the Damn sound for a blunt finish or the Huh sound for a confused pause before the next scene.
關於此聲音
This is a short spoken clip, about two and a half seconds long, in which a voice asks, in plain words, why anyone would think the speaker is fake. The delivery is direct and defensive, with a teasing edge that makes the question sound more like a challenge than a genuine request for an answer. It feels bold, cheeky and a little confrontational.