
And I want you to know that
that is SINCERE. I do feel bad.
The Big Bang Theory Season 9, Episode 13

Okay. Now, see you look SINCERE
but your words are completely false.
The Big Bang Theory Season 10, Episode 6

If you're interested in making
a SINCERE effort to be a good teacher...
The Big Bang Theory Season 8, Episode 2

Not to "Sin City" but to "SINCERE city."
The Big Bang Theory Season 9, Episode 13

A, that was not a joke,
that was a SINCERE request.
The Big Bang Theory Season 6, Episode 24