Sincerity
Etymology
From Latin "sincerus" (pure, clean, unadulterated, sound), of debated further origin. A charming folk etymology claims it comes from "sine cera" ("without wax"), supposedly from honest sculptors who used no wax to hide cracks — but this is almost certainly false, invented to fit the meaning. The real path runs from "unmixed, pure" to "pure of motive, honest in feeling."
noun · /sin-SAIR-uh-tee/
The quality of being genuine in what one says and shows — free of pretense or deceit.
What it names
Use it for the match between inner feeling and outward expression: meaning what you say, and showing what you feel.
Example
The apology’s sincerity was unmistakable — no polish, no excuses, just plain regret.
Related idea
Authenticity is being true to your own self; sincerity, as the critic Lionel Trilling argued, is being true in what you show to others — congruence between avowal and actual feeling. You can be sincerely mistaken about who you really are.
See also