seriousness vs distressfulness

seriousness and distressfulness both are nouns.

Word	Noun	Adjective	Verb	Adverb
seriousness	Yes	No	No	No
distressfulness	Yes	No	No	No

As nouns, seriousness and distressfulness are synonyms defined as:

seriousness and distressfulness: the quality of arousing fear or distress

seriousness (noun)	distressfulness (noun)
the trait of being serious	the quality of arousing fear or distress
the quality of arousing fear or distress
an earnest and sincere feeling