Set in Ulster, love story all about high spirits (7)
I believe the answer is:
elation
'high spirits' is the definition.
('elation' can be a synonym of 'high spirits')
'set in ulster love story all about' is the wordplay.
'set in' is an insertion indicator.
'ulster' becomes 'ni' (Northern Ireland).
'love' becomes 'o' (In tennis, 'love' means 'zero').
'story' becomes 'tale' ('tale' can be a synonym of 'story').
'all about' is a reversal indicator.
'ni' placed around 'o' is 'noi'.
'noi'+'tale'='noitale'
'noitale' in reverse letter order is 'ELATION'.
(Other definitions for elation that I've seen before include "Feeling of joy from toenail" , "Delight, ecstasy" , "Ecstasy -- toenail (anag)" , "It's a great feeling!" , "Toenail (anag) -- delight" .)