Woman's so cruel sadly making revelation (10)
I believe the answer is:
disclosure
'revelation' is the definition.
('disclosure' can be a synonym of 'revelation')
'woman's so cruel sadly' is the wordplay.
'woman's' becomes 'dis' (Di is short for Diana).
'sadly' indicates anagramming the letters.
'so'+'cruel'='socruel'
'socruel' anagrammed gives 'closure'.
'dis'+'closure'='DISCLOSURE'
'making' acts as a link.
(Other definitions for disclosure that I've seen before include "broadcast" , "Laying bare" , "Publication" , "Act of revelation" , "leak" .)