Assert, in the outskirts of town, there's a pub (6)
I believe the answer is:
tavern
'there's a pub' is the definition.
(I've seen this before)
'assert in the outskirts of town' is the wordplay.
'assert' becomes 'aver' (averring is a kind of asserting).
'in the' indicates putting letters inside.
'outskirts of' says to hollow out the word (remove centre letters) (only letters on the outskirts).
'town' with its centre removed is 'tn'.
'aver' put within 'tn' is 'TAVERN'.
(Other definitions for tavern that I've seen before include "Tap house" , "drinking establishment" , "where drink is available" , "An old English pub" , "An old inn or hostelry" .)