Place it just before the reveal in a short edit, then follow it with an awkward moment for the failed excuse, or an anime ahh when the surprise lands instead.
關於此聲音
This 0.72-second clip is Hatsune Miku giving a short, thoughtful hum, her bright synthesized voice rising slightly as if she is considering something. It feels curious and gently sceptical, like a pause before a reply rather than a firm answer. The line comes from the anime Jashin-chan Dropkick.