Love is thwarted in books one writes (8)
I believe the answer is:
novelist
'one writes' is the definition.
'love is thwarted in books' is the wordplay.
'thwarted' is an anagram indicator.
'in' is an insertion indicator.
'books' becomes 'nt' (New Testament).
'love'+'is'='loveis'
'loveis' is an anagram of 'ovelis'.
'ovelis' inserted into 'nt' is 'NOVELIST'.
(Other definitions for novelist that I've seen before include "James was one" , "Fiction-writer" , "Author" , "Book writer" , "I've written" .)