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]
(..) We need you actin' freaky like we need a fuckin' bag on our hip. Okay, let's talk. We think we got a rat in the house. I guarantee we got a rat in the house. What makes you say that? Is that supposed to be funny? Look, we think this place ain't safe. (..)1992 Reservoir Dogs