Principal character gives the girl a ring (4)
I believe the answer is:
hero
I believe this is a double definition.
'principal character' is the first definition.
(I've seen this before)
'the girl a ring' is the second definition.
(I've seen this before)
'gives' is the link.
(Other definitions for hero that I've seen before include "One much admired for courage" , "Male protagonist" , "Leander's suitor" , "Leander's love" , "Leading male role" .)