sure

having or feeling no doubt or uncertainty; confident and assured

“was sure (or certain) she had seen it”

physically secure or dependable

“a sure footing”

certain to occur; destined or inevitable

“sudden but sure regret”

impossible to doubt or dispute

“indisputable (or sure) proof”

exercising or taking care great enough to bring assurance

“be sure to lock the doors”

reliable in operation or effect

“a sure way to distinguish the two”

worthy of trust or confidence

“a sure (or trusted) friend”

definitely or positively (`sure' is sometimes used informally for `surely')

“the results are surely encouraging”

certain not to fail

“a sure hand on the throttle”

infallible or unfailing

“a sure (or true) sign of one's commitment”