"All literature, all art, best seller or worst, must be sincere, if it is to be successful...Only a person with a Best Seller mind can write Best Sellers; and only someone with a mind like Shelley's can write Prometheus Unbound. The delicate forger has little chance with his contemporaries and none at all with posterity."
January 1, 1970
https://en.wikiquote.org/wiki/Sincerity