In conclusion, I say you are the last to suffer (6)
I believe the answer is:
endure
'to suffer' is the definition.
('endure' can be a synonym of 'suffer')
'in conclusion i say you are' is the wordplay.
'in' is an insertion indicator.
'conclusion' becomes 'end' (something's conclusion is its end).
'i say' becomes 'e' (I am not sure about this - if you are sure you should believe this answer much more).
'you are' becomes 'ur' (text or internet abbreviation).
'end'+'e'='ende'
'ende' placed around 'ur' is 'ENDURE'.
'the last' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for endure that I've seen before include "brook" , "Abide" , "Tolerate, put up with" , "Bear, suffer" , "Last or suffer patiently" .)