All you need in this life is ignorance and confidence; then success is sure.

Mark Twain (1835-1910) American writer [pseud. of Samuel Clemens]

Letter to Mrs. Foote (1887-12-02)
    (Source)

First reprinted, upon the letter's rediscovery, in The Los Angeles Times (1930-03-16). A facsimile of the discovered letter (with the above punctuation) can be found in B. DeCasseres, When Huck Finn Went Highbrow (1934).

For more discussion about this quotation's origin: All You Need In This Life Is Ignorance and Confidence; Then Success Is Sure – Quote Investigator®.