a promise that something will be done or will happen, especially a written promise by a company to repair or change a product that develops a fault within a particular period of time
I guarantee that the sun will come up in the morning.
The manufacturer issued a guarantee that the product would be defect-free.
The warranty serves as a guarantee for repairs within a specified period.
Offering a money-back guarantee demonstrates confidence in the product.
The company's guarantee includes free maintenance for the first year.
