King George takes in walk: that's better (7)
I believe the answer is:
gambler
'better' is the definition.
(a gambler is someone who bets)
'king george takes in walk' is the wordplay.
'king george' becomes 'gr' (Georgius Rex).
'takes in' means one lot of letters goes inside another.
'walk' becomes 'amble' (amble is a kind of walk).
'gr' placed around 'amble' is 'GAMBLER'.
'that's' is the link.
(Other definitions for gambler that I've seen before include "One who bets" , "I bet?" , "Speculator" , "Risk taker" , "one who takes chances!" .)