YOU SAID:

James kissed his girlfriend's mum accidentally in the dark last night

INTO JAPANESE

ジェームズは昨夜、暗闇の中で誤ってガールフレンドの母親にキスをした

BACK INTO ENGLISH

James accidentally kissed his girlfriend's mother in the dark last night

INTO JAPANESE

ジェームズは昨夜、暗闇の中で誤ってガールフレンドの母親にキスしてしまいました

BACK INTO ENGLISH

James accidentally kissed his girlfriend's mother in the dark last night