Decide to settle (9)
I believe the answer is:
determine
This clue is a double definition.
'decide' is the first definition.
(I know that decide can be written as determine)
'settle' is the second definition.
(I know that settle can be written as determine)
'to' is the link.
(Other definitions for determine that I've seen before include "Learn" , "Firmly decide" , "Come to a decision" , "Choose" , "Decide - to settle" .)