こそあれ・こそすれ・こそなれMay be X, but certainly not Y

How the contrast works

The first part does not simply concede a fact. It sharply limits the reasonable possibilities: X might happen, or X is the most that can be said. The continuation then rules out Y with a negative expression or an unmistakably opposing claim.

The productive verb pattern

The noun-like pattern

Make the reversal unmistakable

The second half commonly contains an explicit negative, an expression meaning “there is no question of,” or wording equivalent to “far from.” Without a clear reversal, this construction loses the corrective force that distinguishes it from ordinary emphasis.

Nearby patterns

Basic こそ merely emphasizes what comes before it and does not require a reversal. ばこそ strongly presents a reason or condition, rather than granting X and rejecting Y. ものの is a less forceful written concession: it acknowledges a fact and qualifies it, while the target pattern sets up a more polarized correction.