In the dictionary of the seeker of truth there is no such thing as being "not successful." He is or should be an irrepressible optimist because of his immovable faith in the ultimate victory of Truth, which is God.
The history of our race, and each individual’s experience, are sown thick with evidence that a truth is not hard to kill and that a lie told well is immortal.
Though all the winds of doctrine were let loose to play upon the earth, so Truth be in the field, we do injuriously by licensing and prohibiting to misdoubt her strength. Let her and Falsehood grapple; who ever knew Truth put to the worse, in a free and open encounter.
The reason why any one refuses his assent to your opinion, or his aid to your benevolent design, is in you: he refuses to accept you as a bringer of truth, because, though you think you have it, he feels that you have it not. You have not given him the authentic sign.
Something might be true while being harmful and dangerous in the highest degree. Indeed, it might be a basic characteristic of existence that those who know it completely would perish, in which case the strength of a spirit should be measured according to how much of the 'truth' one could still barely endure- or to put it more clearly, to what degree one would require it to be thinned down, shrouded, sweetened, blunted, falsified.