The correct spelling is "definitely" (certainly, absolutely).
The adverb is spelled certainly (positively, indeed).
The idomatic phrase is spelled "of course" (certainly, assuredly).
The likely word is definitely (certainly, absolutely).
The idiomatic expression is spelled "of course" (certainly, undoubtedly).
The likely word is "absolutely" (positively, certainly).
The phrase is spelled "of course" (certainly, surely).
The adverb is spelled certainly (positively, indeed).
The correct spelling is "definitely" (certainly, absolutely).
The correct spelling of the adverb is "absolutely" (certainly, positively).
The idiomatic expression is spelled "of course" (certainly, undoubtedly).
The idomatic phrase is spelled "of course" (certainly, assuredly).
The likely word is definitely (certainly, absolutely).
The word sought may be the adverb "indeed" (certainly, definitely).
Certainly not the one who can not spell 'coolest' !
This seems to be a phonetic version of "how do you spell something that you aren't sure of" which would be an "uncertainty." (Which certainly applies here.)
The possible words are:absolutely - certainly, positivelyactually - really, truly, in fact