一言既出駟馬難追 (jat1 jin4 gei3 ceot1 si3 maa5 naan4 zeoi1) — it is difficult to take back a promise in Cantonese
jatˉ¹一jinˎ₄言gei˗₃既ceotˉ¹出si˗₃駟maaˏ₅馬naanˎ₄難zeoiˉ¹追简 一言既出驷马难追
Mandarin Pinyin: yi4 yan2 ji4 chu1 si4 ma3 nan2 zhui1
Meaning of 一言既出駟馬難追
nounit is difficult to take back a promise