Announcement of a beautiful romance (6)
I believe the answer is:
affair
'romance' is the definition.
(affair can mean a romantic fling)
'announcement of a beautiful' is the wordplay.
'announcement of' becomes 'af' (I can't explain this - if you can you should believe this answer much more).
'a beautiful' becomes 'fair' (I've seen this before).
'af'+'fair'='AFFAIR'
(Other definitions for affair that I've seen before include "Extramarital activity" , "Thing to be done with raffia" , "Vaguely specified concern" , "Concern -- extramarital relationship" , "A romantic intrigue" .)