Sparks when Romeo meets Juliet set back by sides in Verona (9)
I believe the answer is:
activates
'sparks' is the definition.
('activate' can be a synonym of 'spark')
'when romeo meets juliet set back by sides in verona' is the wordplay.
I cannot really see how this works, but
an anagram of 'set' is 'tes' which is located in the answer.
'when romeo meets juliet' could be 'acti' (I've seen this in another clue) and 'acti' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for activates that I've seen is " Stimulates".)