Apt to embrace king that's pleasant (7)
I believe the answer is:
likable
'pleasant' is the definition.
(thesaurus)
'apt to embrace king' is the wordplay.
'apt to' becomes 'liable' (I've seen this before).
'embrace' indicates putting letters inside.
'king' becomes 'k'.
'liable' going around 'k' is 'LIKABLE'.
'that's' is the link.
(Other definitions for likable that I've seen before include "Charming" , "attractive" , "Easy to take to, of pleasant personality" , "Pleasant -- genial" , "Amiable" .)