Would a girl be not so cruel? (8)
I believe the answer is:
ruthless
'cruel?' is the definition.
(I've seen this in another clue)
'would a girl be not' is the wordplay.
'would a girl' becomes 'ruth' (I am not sure about this - if you are sure you should believe this answer much more).
'be not' becomes 'less' (I've seen this in other clues).
'ruth'+'less'='RUTHLESS'
'so' acts as a link.
Can you help me to learn more?
(Other definitions for ruthless that I've seen before include "Callous" , "Unsparing" , "Showing no compassion" , "hard" , "Harsh" .)