The meaning of the word sincere

According to the Webster dictionary, it comes from the latin word sincerus which means whole, pure. As I am fond of stories and meanings, I find particularly interesting the etymology provided by Dan Brown in his book Digital Fortress. He said that "During the Renaissance, Spanish sculptors who made mistakes while carving expensive marble...patched their flaws with cera "(wax) . "A statue that had no flaws...was hailed as a " pure one sin cera. READ THE BOOK!!!