"Truth is mighty and will prevail. There is nothing wrong with this, except that it ain't so"

Mark Twain's quote is a humorous way of revealing his suspicion of the idea that reality is always triumphant. He is indicating that, while it would be great if fact always triumphed, this is not always the case. He is recommending that fact is not always effective enough to conquer falsehoods which in some cases lies and deceptiveness can be more effective. He is also implying that it is naive to believe that fact will constantly prevail, as it often does not. Twain's quote is a pointer that fact is not always the most powerful force and that it is very important to be familiar with this. It is likewise a tip to be watchful in looking for the fact and to not be tricked by lies and deception.