>>279867846
Well, there we go. And yes, it was written "hansei" in English letters in the Japanese original as well. Furinkan notes that:

"The name of the third Mikazukisai's book is "我が反省/Wa ga Hansei", "My Life" or "My Recollections". However, because "Hansei" is written in English, Refuto does not realize it is a homophone and actually means "Hansei" as in "反省" (failures)."

The chapter title had it as "我が半生" with the はんせい as the furigana for Hansei. I guess VIZ did the right thing by just leaving it untranslated.