Assiduously and For certain

Assiduously adverb - In a manner involving great or constant activity.

For certain and assiduously are semantically related. In some cases you can use "For certain" instead an adverb "Assiduously".

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

Assiduously and for certain are semantically related. Sometimes you can use "Assiduously" instead an adverb phrase "For certain".