Certain to return, enthralled by friend reading (7)
I believe the answer is:
perusal
'reading' is the definition.
(perusal is a kind of reading)
'certain to return enthralled by friend' is the wordplay.
'certain' becomes 'sure' ('sure' can be a synonym of 'certain').
'to return' says the letters should be written in reverse.
'enthralled by' is an insertion indicator ('enthral' can mean 'capture').
'friend' becomes 'pal' (pal is a kind of friend**).
'sure' back-to-front is 'erus'.
'erus' put within 'pal' is 'PERUSAL'.
(Other definitions for perusal that I've seen before include "Scanning, reading" , "thorough scan" , "Careful reading" , "Thorough read-through" , "Study or scrutiny" .)