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).