A test of a first-rate work, and a test of your sincerity in calling it a first-rate work, is that you finish it.

-Bennett, (Enoch) Arnold
Things That Have Interested Me,'Finishing Books'.

Sincerity is all that counts is a widespread modern heresy. Think again. Bolsheviks are sincere. Fascists are sincere.Lunaticsaresincere.Peoplewho believethatthe earth is flat are sincere. They can't all be right. Better Sir Martin Mar-All make certain first that you have something to be sincere about, and with.

-Bradwell
  In the Daily Express.

Crystal sincerity hath found no shelter but in a fool's cap.

-Gerard Manley Hopkins
  'Floris in Italy'. Collected in H House and G Storey (eds) The Journals and Papers of Gerard Manley Hopkins (1959), p.42.

The French are polite, but it is often mere ceremonious politeness. A Russian imbues his polite things with a heartiness that compels belief in their sincerity.

-Twain, Mark pseudonym of  Samuel Langhorne Clemens
  The Innocents Abroad.

Freeing hostages is like putting up a stage setöwhich you do with the captors, agreeing on each piece as you slowly put it together. Then you leave an exit through which both the captor and the captive can walk with sincerityand dignity.

-Waite,Terry (Terence Hardy)
  Interviewed on ABC news, 3 Nov.

A littlesincerity isa dangerousthing, and agreat deal of it is absolutely fatal.

-Wilde, Oscar Fingal O'FlahertieWills
Intentions,'The Critic as Artist'.