Doctor urges one to become willing to give (8)
I believe the answer is:
generous
'willing to give' is the definition.
(generous could mean willing to give something)
'doctor urges one' is the wordplay.
'doctor' indicates an anagram.
'urges'+'one'='urgesone'
'urgesone' is an anagram of 'GENEROUS'.
'to become' acts as a link.
(Other definitions for generous that I've seen before include "Liberal, bountiful" , "Princely" , "Willing to give unstintingly" , "Handsome" , "Munificent; liberal" .)