More attractive Parisian ready to marry Romeo (8)
I believe the answer is:
prettier
'more attractive' is the definition.
(I've seen this in another clue)
'parisian ready to marry romeo' is the wordplay.
'parisian ready' becomes 'pret' ('ready' in French).
'to marry' becomes 'tie' ('tie' can be a synonym of 'marry').
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'pret'+'tie'+'r'='PRETTIER'
(Other definitions for prettier that I've seen before include "More lovely" , "More beautiful" , "More attractive in a delicate way" .)