guaranty

noun3

1. •
   An undertaking to answer for the payment of some debt, or the performance of some contract or duty, of another, in case of the failure of such other to pay or perform; a warranty; a security.
2. •
   An assurance or guarantee.

   • ...He had contemplated the match as the fittest for the heir to England's throne, and one that offered the best guaranty for mutual happiness and a vigorous progeniture. — 1886
3. •
   Something serving as a security for such an undertaking.

   • No doubt the city of New York and the State of California contain capital enough for the completion of the entire road,--would subscribe to it, too, upon sufficient guaranties. — 1864