Confronted US agent restraining Bill (5)
I believe the answer is:
faced
'confronted' is the definition.
('face' can be a synonym of 'confront')
'us agent restraining bill' is the wordplay.
'us agent' becomes 'fed' (short for a federal agent).
'restraining' indicates putting letters inside.
'bill' becomes 'ac' (short for account).
'fed' going around 'ac' is 'FACED'.
(Other definitions for faced that I've seen before include "Met" , "Confronted" , "Stomached" , "Dealt with" , "Encountered" .)