If upset, a kiss will make things right (3)

I believe the answer is:

fix

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'right' is the definition.
(thesaurus)

'if upset a kiss' is the wordplay.
'upset' says the letters should be written backwards.
'a kiss' becomes 'x'.
'if' reversed gives 'fi'.
'fi'+'x'='FIX'

'will make things' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Other definitions for fix that I've seen before include "Mend" , "Sort out" , "Fasten" , "Predicament" , "Repair or attach" .)

I've seen this clue in the Evening Standard.

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