confidence game
Also, confidence trick; con game. A swindle in which the victim is defrauded after his or her trust has been won. For example, The police warned of a confidence game in which people were asked to turn over valuables for a so-called appraisal , or The typical confidence trick is easy to spot if you know what to look for, or I almost let myself be taken in by her con game-she seemed so sincere. These terms, which use confidence in the sense of "trust," date from the mid-1800s. They also gave rise to confidence man (or con man) for the swindler.