YOU SAID:

I so sorry for forgetting what you taught me

INTO JAPANESE

あなたが私に教えてくれたことを忘れて本当にごめんなさい

BACK INTO ENGLISH

I'm really sorry to forget what you taught me

INTO JAPANESE

あなたが私に教えてくれたことを忘れて本当に申し訳ありません

BACK INTO ENGLISH

I'm really sorry to forget what you taught me