guarantee

/ˌger-ən-ˈtē/

probably alteration of

noun

  1. guarantor

  2. guaranty

  3. an assurance for the fulfillment of a condition: such as

verb

  1. to undertake to answer for the debt, default, or miscarriage of

  2. to engage for the existence, permanence, or nature of : undertake to do or secure

  3. to give security to

guarantee a loan

noun

  1. a promise that the money a person spent on a product will be returned if the product is not good enough

The software comes with a money-back guarantee.