約やく束そくを破やぶる

expression, godan verb (-ru)

break a promise; go back on one's word; renege

Used when someone fails to keep a promise or commitment. Often implies a breach of trust.

See also: 約束を守る

• 彼かれはよく約やく束そくを破やぶるから、もう信しん用ようできない。

  He often breaks his promises, so I can't trust him anymore.

• 大だい事じな約やく束そくを破やぶってしまって、本ほん当とうに申もうし訳わけない。

  I'm really sorry for breaking such an important promise.