Request with certain satisfaction (8)
I believe the answer is:
pleasure
'satisfaction' is the definition.
(I've seen this in another clue)
'request with certain' is the wordplay.
'request' becomes 'plea' (plea is a kind of request).
'with' says to put letters next to each other.
'certain' becomes 'sure' (synonyms).
'plea'+'sure'='PLEASURE'
(Other definitions for pleasure that I've seen before include "Enjoyment, happiness" , "Happy satisfaction" , "entertainment" , "Gratification of the senses" , "'Enjoyment, delight (8)'" .)