Menno Simons (1496–1561) Dutch theologian, founder of the Mennonites
The Complete Works of Menno Simons https://play.google.com/store/books/details?id=btJAAQAAMAAJ&rdid=book-btJAAQAAMAAJ&rdot=1, by Menno Simons, p.27, January 1, 1871
Me & Rumi (2004)
Menno Simons (1496–1561) Dutch theologian, founder of the Mennonites
The Complete Works of Menno Simons https://play.google.com/store/books/details?id=btJAAQAAMAAJ&rdid=book-btJAAQAAMAAJ&rdot=1, by Menno Simons, p.27, January 1, 1871
“Son, son, I admire your sincerity. Always be sincere - whether you mean it or not.”
Michael Flanders (1922–1975) English writer and performer
The Reluctant Cannibal
“The secret is the secret. Sincerity is the word.”
David Woodard (1964) American writer, conductor and businessman
Breed the Unmentioned (1985)
“The secret of success is sincerity. Once you can fake that you've got it made.”
Jean Giraudoux (1882–1944) French novelist, essayist, diplomat and playwright
As quoted in Murphy's Law Book Two : More Reasons Why Things Go Wrong (1980) by Arthur Bloch, p. 47; similar statements became a routine part of the comedic performances of George Burns.
Attributed
“Always be sincere, even if you don't mean it.”
Harry Truman (1884–1972) American politician, 33rd president of the United States (in office from 1945 to 1953)
Attributed without citation in The Oxford Dictionary of Quotations (1992) by Angela Partington, disputed in The Quote Verifier : Who Said What, Where, and When (2006) by Ralph Keyes, p. 224, as something Truman is not known to have said, nor was likely to have said.
Disputed
Fernando Sabino (1923–2004) Brazilian writer
O encontro marcado [A Time to Meet] (1956), trans. John Procter, p. 210