guarantee definition

1. a written assurance that some product or service will be provided or will meet certain specifications
2. an unconditional commitment that something will happen or that something is true
• examples: there is no guarantee that they are not lying
3. a collateral agreement to answer for the debt of another in case that person defaults
4. give surety or assume responsibility
• examples: I vouch for the quality of my products
5. make certain of
• examples: This nest egg will ensure a nice retirement for us
• examples: Preparation will guarantee success!
6. stand behind and guarantee the quality, accuracy, or condition of
• examples: The dealer warrants all the cars he sells
• examples: I warrant this information