For certain and Without exaggeration

For certain adverb - Definitely or positively (`sure' is sometimes used informally for `surely').

Without exaggeration and for certain are semantically related. In some cases you can use "Without exaggeration" instead an adverb phrase "For certain".

For certain and without exaggeration are semantically related. Sometimes you can use "For certain" instead an adverb phrase "Without exaggeration".