こそが

it is ... that

→ こそ
phrase Uncommon #15,530
it is ... that Emphatically highlights the subject, often conveying “X in particular” or “X above all.”
JA: 努力こそが成功への近道だ。
EN: It is hard work that is the fastest path to success.

われわれこそが人民

We are the people!

— 帰ってきたヒトラー (2015)

マハこそが彼の母親だった

Maha was his mother all along!

— ソング・オブ・ザ・シー 海のうた (2014)

こそが海の男だ

I’m the man of the sea.

— 別れる決心 (2022)

その戦争こそが日本を変えた

It was that war that changed Japan.

勇気こそが今は最大の守り

Courage is our greatest defense now.

— ロード・オブ・ザ・リング/王の帰還 (2003)

真実こそが力だ

Truth is power.

— Брат 2 (2000)

トムこそが真の男だ

Tom is a true man.