诚挚

誠摯

chéngzhì

adjective HSK 7 #13,190

Meanings

Wǒ xiàng nǐ biǎodá zuì chéngzhì de gǎnxiè.

I express my most sincere gratitude to you.

A formal word, commonly seen in written Chinese, speeches, and formal correspondence. In casual speech, 真诚 (zhēnchéng) is more common.

诚 chéng

挚 zhì