surety
sure.ty \'shu.r-*t-e-, 'shu.(*)rt-e-\ \-.ship\ n [ME surte, fr. MF surte`, fr. L securitat-, securitas]security, fr. securus 1: the state of being sure : as 1a: sure knowledge : CERTAINTY 1b: confident manner or behavior : ASSURANCE 2a: a pledge or other formal engagement given for the fulfillment of an und ertaking : GUARANTEE 2b: ground or confidence of security 3a: a sponsor at baptism 3b: one who has become legally liable for the debt, default, or failure in duty (as appearance in court) of another - sure.ty.ship n
Webster's English Dictionary