A Romeo determined warmth of feeling (6)

I believe the answer is:

ardour

'warmth of feeling' is the definition.
(I've seen this before)

'a romeo determined' is the wordplay.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'determined' becomes 'dour' (I've seen this before).
'a'+'r'+'dour'='ARDOUR'

(Other definitions for ardour that I've seen before include "Love and enthusiasm" , "Passion, rapture" , "Great fire" , "Fervour, zeal" , "Fervour or passion" .)

I've seen this clue in The Telegraph.

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