Cold-hearted deuces failed to cut it (7)
I believe the answer is:
succeed
'cut it' is the definition.
I can't judge whether this defines the answer.
'cold-hearted deuces failed' is the wordplay.
'cold' becomes 'C' (eg on taps).
'hearted' is an insertion indicator (some letters go to the heart of the word).
'failed' indicates anagramming the letters.
'deuces' anagrammed gives 'suceed'.
'c' placed into 'suceed' is 'SUCCEED'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for succeed that I've seen before include "what prince royal might do" , "Follow - triumph" , "Follow on - win" , "Follow in order" , "get results" .)