My heartiest greetings to you!

我衷心的问候你！

He bowed me his heartiest thanks.

他向我鞠躬表示他衷心的谢意。

Allow me to offer my heartiest wishes.

请允许我向你表示衷心的问候。

Please accept my heartiest congratulation.

请接受我最诚挚的祝福。

Please accept my heartiest congratulations.

请接受我衷心的祝贺。