guarantee
(a formal oral or written assurance to repair or replace a product if it proves faulty within a stated period)
- This washing machine is still under guarantee.
- We give you a 20-year guarantee against rust.
warranty
(a formal written assurance that the facts specified in the product is true, but if they are not, it will be repaired or replaced)
- The company will replace the part free of charge If the car is still under warranty.
- The warranty coverage is 36 months.