un assailable (adjective) unassailable: certain
Sinonime: absolute, ascertained,
authoritative,
clear,
conclusive, confirmable,
definite, demonstrable,
destined,
determined, establishable,
evident,
firm,
fixed,
genuine,
guaranteed,
hard, having down pat, in the bag, inarguable, incontestable,
incontrovertible, indisputable,
indubitable,
infallible,
irrefutable,
known, on ice,
plain,
positive, predestined, provable,
real,
reliable,
safe, salted away,
set,
sound,
supreme,
sure, sure thing,
true,
trustworthy,
unambiguous,
undeniable, undisputable, undoubted,
unequivocal, unerring, unmistakable, unquestionable, verifiable