readiness vs willingness

readiness and willingness both are nouns.

Word	Noun	Adjective	Verb	Adverb
readiness	Yes	No	No	No
willingness	Yes	No	No	No

As nouns, willingness is a hypernym of readiness; that is, willingness is a word with a broader meaning than readiness:

readiness (noun)	willingness (noun)
prompt willingness	cheerful compliance
a natural effortlessness
(psychology) being temporarily ready to respond in a particular way
the state of having been made ready or prepared for use or action (especially military action)