French phrase
Je ne le ferai plus.
Meaning
I won't do it again.
When to use it
A promise not to repeat the same action. Often said after an apology.
Example dialogue
Tu as pris mon ballon sans me demander !
You took my ball without asking me!
Pardon. Je ne le ferai plus. On rejoue ensemble ?
Sorry. I won't do it again. Shall we play together again?