sure enough vs for certain

sure enough and for certain both are adverbs.

Word	Noun	Adjective	Verb	Adverb
sure enough	No	No	No	Yes
for certain	No	No	No	Yes

As adverbs, sure enough and for certain are synonyms defined as:

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

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

sure enough (adverb)	for certain (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')