Last three children allege they will break their promise (6)

I believe the answer is:

renege

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'promise' is the definition.
The answer and definition can be both to do with communicating as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for renege that I've seen before include "In card games, revoke" , "Don't follow suit when you can" , "Fail to follow suit at cards" , "Go back on an obligation" , "South American cowboy" .)

I've seen this clue in The Irish Times.

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