Earnest-sounding fellow (6)
I believe the answer is:
ernest
'fellow' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for ernest that I've seen before include "American writer . . . . . . Hemingway" , "fellow" , "First name of . . . . . . Hemingway, American novelist" , "A new genre is myth (anag) -- author" , "Name (of dramatic importance!)" .)