相见恨晚

相見恨晚
xiāngjiànhènwǎn
  1. to regret not having met earlier (idiom); It is nice to meet you finally.
  2. It feels like we have known each other all along.

CEDICT

to regret not having met earlier; if only we had met earlier (used to express the happiness when meeting with someone for the first time)

Wiktionary

遗憾认识得太晚。语本《史记．卷一一二．平津侯传》：「天子召见三人，谓曰：『公等皆安在？何相见之晚也！』」形容一见如故，意气相投。宋．方千里〈六么令．照人明豔〉词：「当时相见恨晚，彼此萦心目。」也作「相逢恨晚」。

重編國語辭典

指想要遇到的事情，遗憾相识太晚，已经错过了良好时机

維基詞典

Entry Composition

1 相见 xiāngjiàn
  1. to see each other
  2. to meet in person
2 恨 hèn
  1. to hate
  2. to regret
3 晚 wǎn
  1. evening
  2. night
  3. late