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]
(..) he'll kill her and upload the video. Everyone will see it. The world will see it. The mood will border on insurrection and you will be destroyed, I guarantee you... utterly destroyed. The polling bears that out. You won't just be a disgraced politician, The public, the Palace and the Party insist on compliance. Fuck the Party! Refuse, and I've been advised that we cannot guarantee your physical safety. Or that of your family. I've made arrangements for the broadcast. I can't... (..)2011 TvShow: Black Mirror Title: The National Anthem Season: 1 Episode 1