guarantee

noun | \ ˌgar-ən-ˈtē, ˌgär- \ | guar·an·tee

1. : guarantor

2. : guaranty 1

   a : an agreement by which one person undertakes to secure another in the possession or enjoyment of something

   b : an assurance of the quality or of the length of use to be expected from a product offered for sale often with a promise of reimbursement

4. : guaranty 4, 5 constitutional guarantees