Shine, glimmer (4)
I believe the answer is:
glow
I believe this clue is a double definition.
'shine' is the first definition.
(glow is a kind of shine)
'glimmer' is the second definition.
(thesaurus)
(Other definitions for glow that I've seen before include "Radiate or redden" , "Give out steady light" , "warmth of feeling" , "Gentle, warm light" , "Shine with warmth, emotion" .)