pledge

A solemn promise to do something.

(with the) A promise to abstain from drinking alcohol.

An asset or person temporarily handed over to guarantee the fulfilment of something promised, under threat of permanent loss of the thing handed over; surety, security, hostage.

(law) A bailment of personal property to secure payment of a debt without transfer of title.

The personal property so pledged, to be kept until the debt is paid.

(university slang) A person who has taken a pledge of allegiance to a college fraternity, but is not yet formally approved.

A drinking toast.