vow

To declare or assert.

An earnest promise to perform a specified act or behave in a certain manner, especially a solemn promise to live and act in accordance with the rules of a religious order.

To promise solemnly; pledge. synonym: promise.

To make a pledge or threat to undertake.

To make a vow; promise.

To promise solemnly; undertake, by a solemn promise, as to God or a deity, to do, perform, or give; devote.

To threaten solemnly or upon oath.

To assert or maintain solemnly; asseverate; swear.

To make vows or solemn promises; protest solemnly; asseverate; declare emphatically.

A solemn promise; an engagement solemnly entered into.