Utter the words "Never again" --- and I quite understand (3,2,4)
I believe the answer is:
say no more
'never again and i quite understand' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'utter the words' is the wordplay.
'utter' becomes 'say' (saying is a kind of uttering).
'the words' becomes 'nomore' (I can't justify this - if you can you should give a lot more credence to this answer).
'say'+'nomore'='SAY NO MORE'
Can you help me to learn more?
(Other definitions for say no more that I've seen before include "I understand the implication!" , "Not another word!" , "It speaks for itself" , "Further words are unnecessary" .)