Theatre in Spain to feel discontented (6)
I believe the answer is:
Here is my best explanation:
'feel discontented' is the definition.
I can't judge whether this defines the answer.
'theatre in spain' is the subsidiary indication.
'theatre' becomes 'rep' (I've seen this in other clues).
'spain' becomes 'e' (abbreviation for Espana).
'to' is the link.
(Other definitions for repine that I've seen before include "Plain", "Fret, be discontented", "Be in a state of anxiety", "Fret, about a tree perhaps?", "Be discontented; fret" and "Express discontent".)