The line comes from Fire Emblem Echoes: Shadows of Valentia, the 2017 Nintendo 3DS remake of Fire Emblem Gaiden. Like the rest of the game it is fully voiced, which helped short reaction lines circulate outside the game as standalone clips. Players shared the quote on soundboards and in edits because its wording fits far beyond its original scene, applying to any joke, insult or prediction that turns out to be correct. Its formal phrasing also makes it stand out from more casual reaction sounds.
About this sound
Short voice line from Fire Emblem Echoes: Shadows of Valentia saying I'd laugh were it not true, used as a dry reaction to painfully accurate statements.
This is a brief, fully voiced quote delivered in a flat, weary tone that lands somewhere between amusement and resignation. The speaker starts as if about to laugh, then immediately undercuts it, making the line feel dry and a little bitter. There is no music or effect underneath, just the clear voice line on its own, which makes the pause and inflection easy to hear in its two and a half seconds. It works because the reaction is understated rather than exaggerated, capturing that moment when something is funny only because it is uncomfortably accurate.