“It is a principle of his that no man who was not a true gentleman at heart, ever was, since the world began, a true gentleman in manner. He says, no varnish can hide the grain of the wood; and that the more varnish you put on, the more the grain will express itself.”
– Charles Dickens
Great Expectations, Chapter 22. Pip’s friend Herbert Pocket explains to him about Miss Havisham’s disastrous relationship with Compeyson, quoting his father Matthew Pocket about the conman. Truly good actions come from a good heart and Compeyson did not have a true manner or heart, he says. His father’s metaphor about varnish being unable to hide the grain of the wood is telling us that a person’s true nature cannot be faked.