He's the kindest and sincerest person I've ever met.

他是我见过的最和善、最真诚的人。

《柯林斯英汉双解大词典》

That is our sincerest hope.

是为至盼。

《新英汉大辞典》

Please accept my sincerest and deepest apology.

请接受我最诚挚、最深刻的道歉。

youdao

The mockery you might say mockery of Socrates remains one of the sincerest forms of flattery; they took him very seriously.

这些嘲弄，可以这么说,对苏格拉底的嘲弄,仍是最真诚的奉承型式之一；,他们很把他当一回事。

耶鲁公开课 - 政治哲学导论课程节选

What could be more fitting than to do so by buying its sincerest flatterer?

ECONOMIST: Selling books in China

We would like to take this opportunity to offer our sincerest condolences to Mr Lubbock's family.

BBC: NEWS | UK | England | Essex | Police reject Barrymore claims

For many consumers, that imitation is not the sincerest form of flattery, or winning any real friends.

FORBES: Customizing Strategy in a Digital World