arm, armor, ascertain, assure, attest, back, be sponsor for, bless, bond, certify, champion, cinch, clear up, clinch, cloak, compass about, confirm, copyright, countersecure, cover, cushion, decide, defend, determine, dismiss all doubt, endorse, ensure, establish, fence, fend, find out, fix, get at, guarantee, guaranty, guard, harbor, haven, keep, keep from harm, make certain, make no doubt, make no mistake, make safe, make sure, make sure of, nail down, nestle, patent, police, protect, reassure, register, remove all doubt, ride shotgun for, safeguard, screen, secure, see that, see to it, set at rest, settle, shelter, shield, shroud, sign, sign for, sort out, sponsor, stand behind, stand up for, subscribe to, undersign, underwrite, warrant
give security, give bail, give substantial bail, go bail, pawn, impawn, spout, mortgage, hypothecate, impignorate, guarantee, warrant, warrantee, assure, accept, indorse, underwrite, insure
, cosign, countersign, sponsor, cosponsor, execute, stamp, sign, seal, let, sett, grant a lease, take a lease, hold a lease, hold in pledge, lend on security.
be certain, stand to reason, render certain, insure
, ensure, assure, clinch, make sure, determine, decide, set at rest, make assurance double sure, know, dogmatize, lay down the law.