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 quite understand how this works, but
an anagram of 'set' is 'tes' which is within the answer.
'when romeo meets juliet' could be 'acti' (I've seen this in another clue) and 'acti' is present in 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".)