What is "experto crede"

Latin, "take it from one who knows" ("Aeneid," xi.283); dative singular of expertus (see expert (adj.)) + imperative singular of credere (see credo).

experto crede is a Latin motto which means Trust in one experienced; literally: "(the/an) expert trust". It is usually used by an author as an aside to the reader, and may be loosely translated as: "trust me", "trust the expert", "believe one who has tried it", or "have faith in experience". When "crede" is followed by a personal name (e.g., crede John Smith), the expert in question is the name given.

In the variant form experto credite it is a quotation from the Aeneid by Virgil (Book XI, line 283).