The perpetrator of a confidence trick (or "con trick") is often referred to as a confidence (or "con") man, con-artist, or a "grifter". Samuel Thompson (1821-1856) was the original "confidence man." Thompson was a clumsy swindler who asked his victims to express confidence in him by giving him money or their watch rather than gaining their confidence in a more nuanced way. A few people trusted Thompson with their money and watches. Thompson was arrested in July 1849. Reporting about this arrest, Dr. James Houston, a reporter of the New York Herald, publicized Thompson by naming him the "Confidence Man." Although Thompson was an unsuccessful scammer, he gained reputation of a genius operator mostly because Houston's satirical writing wasn't understood. The National Police Gazette coined the term "confidence game" a few weeks after Houston first used the name, the "confidence man."Oh! So "confidence man" — a word about the human failure to grasp what's in the mind of the person using language — was first read with a failure to grasp what was in the mind of the person using the language.
Back in 1857, Herman Melville published "The Confidence-Man: His Masquerade." Excerpt:
"If I am [warm against these bears], it is less from the remembrance of their stratagems as to our stock, than from the persuasion that these same destroyers of confidence, and gloomy philosophers of the stock-market, though false in themselves, are yet true types of most destroyers of confidence and gloomy philosophers, the world over. Fellows who, whether in stocks, politics, bread-stuffs, morals, metaphysics, religion—be it what it may—trump up their black panics in the naturally-quiet brightness, solely with a view to some sort of covert advantage. That corpse of calamity which the gloomy philosopher parades, is but his Good-Enough-Morgan."Trump up their black panics in the naturally-quiet brightness...
Further reading: What's a "Good-Enough-Morgan"?