0 honestly and without pretending or lying:
I'm sincerely grateful.
1 Sincerely or Sincerely yours is a common way to end a letter to someone who is not a friend or family member, before you sign your name.
2 used at the end of a formal letter before you sign your name
The author is sincerely grateful to an anonymous reviewer for the detailed comments which greatly improved the paper.
I sincerely hope that his sons become geologists showing the same amount of commitment as their father to a task well done.
Any time an official sincerely swears an oath to uphold the constitution, she is also engaged in an act of self-constraint.
In the first iteration, they are just voting sincerely.
If their 'second-best' candidates are so far apart ideologically from their own ideal point, voters may vote sincerely to manifest their protest.
If the lessons of history have been recognized and sincerely repented, we should do better in the future.
Accordingly, the reasons that people are sincerely prepared to offer for the opinions and beliefs they hold are not the "real" reasons.
They presented their proposals - sincerely as well as rhetorically - as following and catching up with other major scientific nations.