Profitable and extremely resolute venture I am arranging (12)
I believe the answer is:
remunerative
'profitable' is the definition.
('remunerative' can be similar in meaning to 'profitable')
'extremely resolute venture i am arranging' is the wordplay.
'extremely' means to remove the middle letters.
'arranging' indicates an anagram.
'resolute' with its centre removed is 're'.
'venture'+'i'+'am'='ventureiam'
'ventureiam' is an anagram of 'munerative'.
're'+'munerative'='REMUNERATIVE'
'and' is the link.
(Other definitions for remunerative that I've seen before include "Profitable" , "(Of work) paying" .)