誓ちかい合あう

godan verb (-u)

swear together; make a joint vow; pledge to each other

Describes two or more people making a mutual promise or oath. Often used in romantic, friendship, or ceremonial contexts.

• 二人ふたりは永えい遠えんの愛あいを誓ちかい合あった。

  The two swore eternal love to each other.

• 仲なか間またちと成せい功こうを誓ちかい合あう。

  We pledge success together with our comrades.