Place it just before the reveal in an edit, then follow it with a cheer once the answer is shown, and use a shocked reaction before it when the search looked hopeless.
關於此聲音
This is a short Japanese voice clip, just over three seconds long, in which an excited speaker repeats 'Kore da! Kore da! Kore da wa!' — 'This is it! This is it! This is the one!' — with rising energy on each repeat. It feels like a sudden eureka moment, triumphant and relieved, the sound of recognising the exact answer, person or thing you were looking for.