Question: The Possible Origins of the Words Sincere and Sincerely
The origin of the word sincere is disputed, although the popular etymology has it coming from words for 'without wax.'
It is commonly believed that sincere
comes from two Latin words - sine
'without' and cera
'wax'. Although even that much is challenged, there are two explanations for how 'without wax' came to be an important claim, both involving craftsmen, who during the Republic of Rome, would generally have been slaves or foreigners. Some think that marble workers would cover imperfections in the stone with wax, much as modern homemakers or unscrupulous antique dealers might rub wax to hide a scratch in wood. Another idea for the origin of sincere has more ominous consequences. Since cement
was more expensive than wax, unscrupulous brick layers would sometimes employ it -- at least that's the story. When it melted, bricks could shift and structures collapse. So the claim that something was sine cera would be an important guarantee.
The Online Etymology Dictionary says it may come from sem-, sin-, roots for 'one' and crescere 'growth'.