自分自身で

by oneself

→ 自分
phrase Rare #30,290
by oneself Emphatically means doing something personally or through one's own efforts; stronger than 自分で.
JA: この問題は自分自身で解決しなければならない。
EN: You have to solve this problem yourself.

自分自身で責任を取る

Take responsibility for yourself.

— ラスト、コーション (2007)

彼はそう言ったさらに驚いたことに自分自身でそれを実行した

He said that, but even more surprisingly, he carried it out himself.

トム実際自分自身でそれをやった

Did Tom actually do it himself?

言語習得うまくやりたいのなら自分自身で学ぶこと

If you want to become good at learning a language, teach yourself.

その役人自分自身でその苦情処理出来なかった

The official couldn’t handle the complaint himself.