返せば

if (someone) returns, gives back

→ 返す

返せ return, give back + ば Conditional (if/when)

verb · conditional Rare #41,072

if (someone) returns, gives back Conditional form of 返す, used for “if” or “when” someone returns or gives something back.

JA: 本を返せば、図書館に帰れます。

EN: If you return the book, you can go home from the library.

Conjugation of 返す

Conditional

I... what should I say back? Is “yes” okay?

— Good Luck, Have Fun, Don't Die (2026)

If you return the case, I won't kill you.

— ブレット・トレイン (2022)

You can pay it back once you make a profit.

— イップ・マン序章 (2008)

If you return the detonator, everyone will be saved.

— ダイ・ハード (1988)