The meaning of guarantee is a promise to answer for the payment of a debt or the performance of a duty of another in case of the other's default or miscarriage : How to use guarantee in a. A promise or assurance, especially one in writing, that something is of specified quality, content, benefit, etc., or that it will perform satisfactorily for a given length of time.
A guarantee is money or something valuable which you give to someone to show that you will do what you have promised. In english law, a guarantee is a contract whereby the person (the guarantor) enters into an agreement to pay a debt, or effect the performance of some duty by a third person who is primarily liable for that. Definition of guarantee verb in oxford advanced learner's dictionary.
The washer comes with a guarantee against major defects. The software comes with a money-back guarantee. To guarantee is to promise or to a make binding agreement.
If a baseball player guarantees his team will win the world series, he better not lead the league in strikeouts. One in writing, that something is of specified quality, content, benefit, etc., or will perform satisfactorily for a given length of time: A money-back guarantee on an appliance.