こそすれ

こそすれ grants one thing and flatly denies its opposite: "if anything X, and certainly not Y". It follows a する-noun or a verb's ます-stem, and the second half of the sentence is negative.

すれ is an old form of する that classical Japanese required after こそ. It survives only in this pattern and never changes shape.

する-nouns and ます-stems

A する-noun such as かんしゃ感謝, あっか悪化 or そんけい尊敬 drops する and takes こそすれ in its place. Any other verb goes into the ます-stem, not the dictionary form: ×増えるこそすれ.

The verb keeps its own transitivity. あっか悪化する means "get worse", so making something worse needs the causative あっか悪化させる. And when the subject is the thing being praised or blamed, the verb goes into the passive.

• × 問題を悪化こそすれ → 問題を悪化させこそすれ
• × 彼の行動は賞賛こそすれ → 彼の行動は賞賛されこそすれ

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こそすれ belongs to essays, editorials and speeches, and it carries conviction, sometimes indignation. In conversation, the same idea comes out as 〜ことはあっても〜ない or 〜はしても〜はしない.