Twain: it's easier to fool...

(*) presumed author

"Presumed author" because (I quote ): "In December 1906 Mark Twain dictated remarks for his autobiography which was being published in installments in “The North American Review”. Twain’s comments included the following statement which semantically aligns with the saying under investigation although it is distinct: How easy it is to make people believe a lie, and how hard it is to undo that work again! "