Steadfastness is a related term of dependability.
As nouns the difference between steadfastness and dependability
is that steadfastness is loyalty in the face of trouble and difficulty while dependability is the characteristic of being dependable; the ability to be depended upon.
steadfastness
English
Noun
Loyalty in the face of trouble and difficulty.
Steadfast resolution.
dependability
English
Noun
(dependabilities)
The characteristic of being dependable; the ability to be depended upon.