Антонимом uncertain

perceptibly unmistakably as the case may be palpably to nth degree without fail sure as can be in all likelihood at first sight plausibly indisputably straight out like enough most likely conspicuously clearly rain or shine unshakably surely nth degree recognizably assumably all in all at a glance speciously discernibly incontestably obviously tangibly beyond question undoubtedly prominently it seems that reputably beyond doubt nothing else but believably intuitively professedly irrefutably come hell or high water patently presumptively manifestly come what may for real to all appearances unambiguously unfailingly on the money fixedly with certainty no doubt to be sure the very thing infallibly sure enough visibly categorically undeniably hypothetically audibly translucently recognisably expediently doubtless on the face of it imaginably utterly probably in plain sight beyond shadow of doubt noticeably it would seem far away absolutely admittedly in all probability penetratingly overtly no ifs ands or buts for certain feasibly presumably transparently without doubt lucidly definitely inexorably to the nth degree very thing decisively practicably sure as hell it appears that no strings attached apparently be sure incontrovertibly no ifs ands or buts about it in toto one can assume unequivocally on the button unerringly beyond any doubt sonorously to the core as likely as not explicitly beyond shadow of a doubt

sure certain clear decided definite determined predictable reliable resolved safe secure settled trustworthy unchanging undoubted foreseeable

exact