Vow

You touch two willing Humanoids (one of which may be yourself) and spend a minute repeating a promise to each other in the same language, which you must both understand. The promises may be identical, but may be different. When the spell ends, the two Humanoids are bound by the promise(s) made to each other and the two rings used in the spells casting appear on the hands of the two targets. If one of the targets breaks the promise they made, they instantly die, ignoring the effects of the Death Ward spell, and can only be brought back to life by means of a spell of 6th level or higher. Additionally, the other Humanoid is no longer bound by the Vow spell. Whether or not a course of action breaks or would break the promise made is at the Dungeon Master's discretion.

This spell cannot be dispelled except by a Dispel Magic spell cast at 6th level, a Remove Curse spell cast at 6th level or by a Wish spell.