The courage of a he-man (5)
I believe the answer is:
heart
'the courage' is the definition.
(heart is a kind of courage)
'a he-man' is the wordplay.
'man' becomes 'art' (**).
'he'+'art'='HEART'
'of' acts as a link.
(Other definitions for heart that I've seen before include "It beats" , "Feeling" , "Middle" , "Cardiac organ" , "Crux" .)