Conversion of Saint Paul, short of a romantic ceremony (8)
I believe the answer is:
nuptials
'romantic ceremony' is the definition.
(nuptials are the ceremonies of a wedding)
'conversion of saint paul short of a' is the wordplay.
'conversion of' indicates anagramming the letters (I've seen 'conversion' mean this).
'short of' is a deletion indicator.
'saint'+'paul'='saintpaul'
'saintpaul' with 'a' taken away is 'sintpaul'.
'sintpaul' with letters rearranged gives 'NUPTIALS'.
(Other definitions for nuptials that I've seen before include "Marriage ceremonies" , "Wedding - suit plan (anag)" , "A wedding or marriage" , "Plural noun meaning wedding" , "Wedding ceremony" .)