Warm feeling about tax cut is pretence (11)
I believe the answer is:
affectation
'is pretence' is the definition.
(I have seen 'Deliberate pretence' mean 'affectation' so perhaps 'pretence' could also mean 'affectation')
'warm feeling about tax cut' is the wordplay.
I cannot really see how this works, but
'feeling' could be 'affect' (affect is a kind of feeling) and 'affect' is found within the answer.
'about' could be 'on' (as in a book 'on' a certain topic) and 'on' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for affectation that I've seen before include "Deliberate pretence" , "Show evidence of" , "retence" , "unnatural appearance" .)