If you're interested in making
a SINCERE effort to be a good teacher...
The Big Bang Theory Season 8, Episode 2
And I want you to know that
that is SINCERE. I do feel bad.
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
...and if I can figure out a way to do so
and sound SINCERE, I will.
The Big Bang Theory Season 4, Episode 9
Okay. Now, see you look SINCERE
but your words are completely false.
The Big Bang Theory Season 10, Episode 6