Attributed. E.g., Vol 24, Encyclopedia Britannica of Arts, Sciences, and General Literature, page 721 https://books.google.com/books?id=_GlJAAAAYAAJ&pg=PA721&lpg=PA721&dq=truth+wotton+confound+advice&source=bl&ots=-cGk3UDLLj&sig=ltOR1xtI9WFic1JWKiFmIZ8Yce0&hl=en&sa=X&ved=0ahUKEwjVkZCsj-jRAhXCyFQKHTmsCkAQ6AEIODAG#v=onepage&q=truth%20wotton%20confound%20advice&f=false (9th Ed. 1894).
Compare Mark Twain who, in Following the Equator, said "When in doubt, tell the truth" (which is often mis-quoted as containing an additional clause providing "it will confound your enemies and astound your friends").
“When in doubt tell the truth. It will confound your enemies and astound your friends.”
Source: Necromancer (1962), Chapter 5 (p. 36)
“The young are not afraid of telling the truth.”
Source: The Diary of a Young Girl
“One that confounds good and evil is an enemy to the good.”
15 February 1788
On the Impeachment of Warren Hastings (1788-1794)
Source: Zen and the Art of Motorcycle Maintenance (1974), Ch. 1
Source: Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values
“Truth is a discredited commodity among diplomats.”
Source: Empire novels (1950–1952), The Currents of Space (1952), Chapter 6 “The Ambassador” (p. 64)
“To tell the truth is very difficult, and young people are rarely capable of it.”
Source: Towing Jehovah (1994), Chapter 2, “Priest” (p. 44)
1860s, Our Composite Nationality (1869)
Context: It is objected to the Chinaman that he is secretive and treacherous, and will not tell the truth when he thinks it for his interest to tell a lie. There may be truth in all this; it sounds very much like the account of man’s heart given in the creeds. If he will not tell the truth, except when it is for his interest to do so, let us make it for his interest to tell the truth. We can do it by applying to him the same principle of justice that we apply to ourselves. But I doubt if the Chinese are more untruthful than other people. At this point I have one certain test. Mankind are not held together by lies. Trust is the foundation of society. Where there is no truth, there can be no trust, and where there is no trust, there can be no society. Where there is society, there is trust, and where there is trust, there is something upon which it is supported. Now a people who have confided in each other for five thousand years; who have extended their empire in all directions until it embraces one-fifth of the population of the globe; who hold important commercial relations with all nations; who are now entering into treaty stipulations with ourselves, and with all the great European powers, cannot be a nation of cheats and liars, but must have some respect for veracity. The very existence of China for so long a period, and her progress in civilization, are proofs of her truthfulness. This is the last objection which should come from those who profess the all-conquering power of the Christian religion. If that religion cannot stand contact with the Chinese, religion or no religion, so much the worse for those who have adopted it. It is the Chinaman, not the Christian, who should be alarmed for his faith. He exposes that faith to great dangers by exposing it to the freer air of America. But shall we send missionaries to the heathen to right to come to us? I think a few honest believers in the teachings of Confucius would be well employed in expounding his doctrines among us.
