As nouns the difference between painfulness and gainfulness
is that painfulness is the state or quality of being painful, of causing pain while gainfulness is the state or quality of being gainful; profitableness.
painfulness
English
Noun
(-)
The state or quality of being painful, of causing pain.
The state or quality of being tedious, of requiring great care.
gainfulness
English
Noun
(-)
The state or quality of being gainful; profitableness.