declarative vs asserting

declarative is a noun but asserting is not a noun.

Word	Noun	Adjective	Verb	Adverb
declarative	Yes	Yes	No	No
asserting	No	Yes	No	No

As adjectives, declarative and asserting are synonyms defined as:

declarative and asserting: relating to the use of or having the nature of a declaration

Other synonyms of declarative include declaratory.

declarative (noun)	asserting (noun)
a mood (grammatically unmarked) that represents the act or state as an objective fact

declarative (adjective)	asserting (adjective)
relating to the use of or having the nature of a declaration	relating to the use of or having the nature of a declaration
relating to the mood of verbs that is used simple in declarative statements