I wanted to see if this was really a quote by Mark Twain and found this article on snopes which states that there is no evidence linking this quote to Twain. Instead there is a quote from one of his books with a similar sentiment so its possible it was someone paraphrasing Twain

https://www.snopes.com/fact-check/did-mark-twain-say-its-easier-to-fool-people-than-to-convince-them-that-they-have-been-fooled/

So, ironically, the quote is meta AF.