pleasantness vs amenity

pleasantness and amenity both are nouns.

Word	Noun	Adjective	Verb	Adverb
pleasantness	Yes	No	No	No
amenity	Yes	No	No	No

As nouns, amenity is a hyponym of pleasantness; that is, amenity is a word with a more specific, narrower meaning than pleasantness:

Other hyponyms of pleasantness include pleasingness, agreeableness, enjoyableness, niceness.

pleasantness (noun)	amenity (noun)
the quality of giving pleasure	pleasantness resulting from agreeable conditions
the feeling caused by agreeable stimuli; one pole of a continuum of states of feeling