guarantee

Noun

• a collateral agreement to answer for the debt of another in case that person defaults

• an unconditional commitment that something will happen or that something is true
  • there is no guarantee that they are not lying
    

• a written assurance that some product or service will be provided or will meet certain specifications

Verb

• stand behind and guarantee the quality, accuracy, or condition of
  • The dealer warrants all the cars he sells
    
  • I warrant this information
    

• promise to do or accomplish
  • guarantee to free the prisoners
    

• make certain of
  • This nest egg will ensure a nice retirement for us
    
  • Preparation will guarantee success!
    

• give surety or assume responsibility
  • I vouch for the quality of my products
    

Related words

• Synonyms: 
  guaranty , warrant , warrantee , warranty , undertake , ensure , insure , assure , secure , vouch