Couple of negatives raised about one tear-jerker (5)
I believe the answer is:
onion
'tear-jerker' is the definition.
(cutting onions can make you cry)
'couple of negatives raised about one' is the wordplay.
'couple of negatives' becomes 'nono' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'raised' is a reversal indicator (going up in a down clue).
'about' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'nono' reversed gives 'onon'.
'onon' placed around 'i' is 'ONION'.
Can you help me to learn more?
(Other definitions for onion that I've seen before include "Hot dog topping" , "veggie" , "Shape of Russian dome" , "Plant with edible bulb" , "Alliaceous plant" .)