sure enough vs certainly

sure enough and certainly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
sure enough	No	No	No	Yes
certainly	No	No	No	Yes

As adverbs, sure enough and certainly are synonyms defined as:

sure enough and certainly: definitely or positively (`sure' is sometimes used informally for `surely')

Other synonyms of sure enough include for certain, for sure, sure, sure as shooting, surely.

sure enough (adverb)	certainly (adverb)
as supposed or expected	definitely or positively (`sure' is sometimes used informally for `surely')
definitely or positively (`sure' is sometimes used informally for `surely')