Affirm it's the little street on the right (4)
I believe the answer is:
aver
'affirm' is the definition.
(I know that affirm can be written as aver)
'the little street on the right' is the wordplay.
'the little street' becomes 'ave' (short for avenue. I am not sure about the 'little' bit.).
'on' is a charade indicator (letters next to each other).
'the right' becomes 'r' (common abbreviation).
'ave'+'r'='AVER'
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for aver that I've seen before include "Formally state" , "Assert to be the case" , "protest" , "State firmly - don't rave" , "Maintain - state" .)