One's true thoughts and nature are revealed when one drinks wine.
Origin of in-vino-veritas
- L, lit., in wine there is truth: a quotation from Pliny the Elder
From Webster's New World College Dictionary, 5th Edition
- From Latin: in (“in”) + vīnō, the ablative singular of vīnum (“wine”) + vēritās (“truth”). Thus, “in wine there is truth”. First attested, as volgoque veritas iam attributa vino est, in the Naturalis Historia (XIV, 141) of Pliny the Elder.