"He knows much of what men paint themselves would blister in the light of what they are"

This quote is suggesting that people typically present themselves in a way that is different from their true nature. People might paint themselves in a positive light, but if their real nature was revealed, it would certainly be viewed as something unfavorable. It implies that individuals are not always straightforward regarding that they are and what they do. It also recommends that there is someone that knows the fact concerning people, and that this person knows the discrepancy between what people provide themselves as and also who they truly are. This quote is a tip to be honest as well as authentic in our lives, as well as to not attempt to hide our true selves from the world.