I have moved on to another Laurie King book, one in which alchemy is revealed as the root of the plot. In it, she says that the literal meaning of the word sincere is "without wax" (meaning, I think, that wax had often been used to hide the true nature of a substance; thus one without a wax covering was pure and unadulterated). I'm not finding verification of this in the dictionaries I've checked. Can anyone tell me whether she is correct?