Certain country backed deporting one journalist (7)
I believe the answer is:
assured
'certain' is the definition.
(I've seen this before)
'backed deporting one journalist' is the wordplay.
'backed' shows that the letters should be reversed in order.
'deporting' becomes 'russ' (I can't explain this - if you can you should give a lot more credence to this answer).
'one' becomes 'a'.
'journalist' becomes 'ed' (short for editor).
'russ'+'a'='russa'
'russa' written backwards gives 'assur'.
'assur'+'ed'='ASSURED'
'country' acts as a link.
This may not be right. It may be part of another bit of the clue.
(Other definitions for assured that I've seen before include "Beyond doubt" , "Self-confident" , "Confident, secure" , "Informed with certainty and confidence" , "Secured" .)