The software comes with a 'money-back guarantee'. [=a promise that the money you spend on a product will be returned if the product is not good enough]
We used our house as a 'guarantee' for the loan. [=we said that the bank could take our house if we did not pay back the loan]
There is no 'guarantee' that they will approve the contract. [=there is no way to be sure that they will approve it]
(..) Bye, Dad. Bye, Dad. Bye, son. Barbara. l don't understand it. Here this thing has a lifetime guarantee and it breaks. Had to clean the tank myself, take the fish out, put 'em in bags and... Where'd the fish go? Come on, Peach! (..)2003 Finding Nemo