confidence trick

A confidence trick (synonyms include confidence game, confidence scheme, scam and stratagem) is an attempt to defraud a person or group after first gaining their confidence, used in the classical sense of trust. Confidence tricks exploit characteristics of the human psyche such as dishonesty, honesty, vanity, compassion, credulity, irresponsibility, naïveté and greed.

https://en.wikipedia.org/wiki/Confidence_trick