Damsel endlessly in distress? Here's a knight in shining armour (7)
'a knight in shining armour' is the definition.
(term for a legendary knight)
'damsel endlessly in distress?' is the wordplay.
'damsel' becomes 'lady'.
'endlessly' means to remove the last letter.
'in' indicates putting letters inside.
'distress?' becomes 'pain' (distress is a kind of pain).
'lady' with its final letter removed is 'lad'.
'lad' put within 'pain' is 'PALADIN'.
'here's' is the link.
(Other definitions for paladin that I've seen before include "Knightly champion", "Knight errant; a peer of Charlemagne", "Heroic knight - aid plan (anag)", "Chivalrous knight", "Historical knight".)