“Truth in all its kinds is most difficult to win; and truth in medicine is the most difficult of all.”

To A Friend Whose Work Has Come To Nothing http://poetry.poetryx.com/poems/1723/
Responsibilities (1914)
Context: Now all the truth is out,
Be secret and take defeat
From any brazen throat,
For how can you compete,
Being honour bred, with one
Who, were it proved he lies,
Were neither shamed in his own
Nor in his neighbours’ eyes?
Bred to a harder thing
Than Triumph, turn away
And like a laughing string
Whereon mad fingers play
Amid a place of stone,
Be secret and exult,
Because of all things known
That is most difficult.

Source: Last and Lost Poems

"Dawn Powell: The American Writer" (1987)
1980s, At Home (1988)

Source: A Room with a View (1908), Ch.1

This means ‘Artistic Integrity’ to me.
Talkings about Chopin and Schumann

As quoted in Kapil Sibal Waxes Poetic http://blogs.wsj.com/indiarealtime/2012/01/21/kapil-sibal-waxes-poetic/, Wall Street Journal (21 January 2012)

Adam Bede (1859)
Context: These fellow-mortals, every one, must be accepted as they are: you can neither straighten their noses, nor brighten their wit, nor rectify their dispositions; and it is these people — amongst whom your life is passed — that it is needful you should tolerate, pity, and love: it is these more or less ugly, stupid, inconsistent people whose movements of goodness you should be able to admire — for whom you should cherish all possible hopes, all possible patience. And I would not, even if I had the choice, be the clever novelist who could create a world so much better than this, in which we get up in the morning to do our daily work, that you would be likely to turn a harder, colder eye on the dusty streets and the common green fields — on the real breathing men and women, who can be chilled by your indifference or injured by your prejudice; who can be cheered and helped onward by your fellow-feeling, your forbearance, your outspoken, brave justice.
So I am content to tell my simple story, without trying to make things seem better than they were; dreading nothing, indeed, but falsity, which, in spite of one's best efforts, there is reason to dread. Falsehood is so easy, truth so difficult. The pencil is conscious of a delightful facility in drawing a griffin — the longer the claws, and the larger the wings, the better; but that marvellous facility which we mistook for genius is apt to forsake us when we want to draw a real unexaggerated lion. Examine your words well, and you will find that even when you have no motive to be false, it is a very hard thing to say the exact truth, even about your own immediate feelings — much harder than to say something fine about them which is not the exact truth.