blissfulness vs bliss

blissfulness and bliss both are nouns.

Word	Noun	Adjective	Verb	Adverb
blissfulness	Yes	No	No	No
bliss	Yes	No	No	No

As nouns, blissfulness and bliss are synonyms defined as:

Other synonyms of blissfulness include cloud nine, seventh heaven, walking on air.

blissfulness (noun)	bliss (noun)
a state of extreme happiness	a state of extreme happiness