When  F. Scott Fitzgerald told this to Michel Mok in 1936,  he was very ill with alcoholism.  It’s a sad thought to think so many writers, artists, and the like are plagued with the black dog and self-doubt. When Fitzgerald wrote about utter confidence, he was speaking a truth. As a writer, you have to believe in your project, no matter what  hard knocks it will take. This is not to say that all common sense and helpful criticisms should be ignored, for that would be blind faith. The faith Fitzgerald is talking about is the belief that what one has to say, to create, to write, is valid, it is not nonsense. The story is good, the idea is worthwhile to pursue, for without that honest belief, no amount of hard work will surpass the obstacles thrown in the way, obstacles that sometimes I believe are there to prove or disprove the writer’s belief in himself.