What potion forces someone to tell the truth?

The story behind the answer

Veritaserum is the canonical truth potion in the Wizarding World: just a few drops compel the drinker to answer questions honestly. Dumbledore uses it in The Goblet of Fire to expose Barty Crouch Jr. after the Triwizard Tournament, and the Ministry tightly regulates its use.

It’s not flawless—skilled Occlumens can resist, antidotes exist, and administering it without permission is illegal (Umbridge tried at Hogwarts). Memory tip: “veritas” is Latin for truth, and “serum” suggests a potent liquid. The other options (Confessio Elixir, Truth Extract, Honesty Brew) aren’t canon, making Veritaserum the definitive answer.