Trust those following Orwell regularly (4,2)
I believe the answer is:
rely on
'trust' is the definition.
(relying on is a kind of trusting)
'those following orwell regularly' is the wordplay.
'those' becomes 'yon' (historic English pronoun equivalent to 'those').
'following' means one lot of letters go next to another.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternate letters of 'orwell' are 'rel'.
'yon' after 'rel' is 'RELY ON'.
(Other definitions for rely on that I've seen before include "Put trust in" , "Trust, be confident in" , "Trust in with confidence" .)