然さこそ

expression

surely; certainly; no doubt

Archaic expression used in classical Japanese to emphasize certainty or strong conviction. Not used in modern speech.

• 古こ典てんの文ぶん章しょうに「然さこそあらめ」といった表ひょう現げんが見みられる。

  In classical texts, you can find expressions like 'surely it must be so'.