Explanation
An emphatic pattern meaning 'it may be X, but definitely not Y.' Often pairs with a negative statement.
Formation
Noun + こそすれ + (negative or contrasting statement)
Detailed explanation
「Noun/Verb-ます形 + こそすれ」emphasizes that while one aspect (X) might exist or be true, another aspect (Y) absolutely does not. It's frequently used with negative expressions (e.g., 〜ない、〜できない) to strongly deny the second possibility.
Examples
Kansha koso sure, hinan nado dekimasen.
I might feel grateful, but I could never criticize.
Isogashisa koso sure, taikutsu suru koto wa arimasen.
I may be busy, but I'm never bored.
Koukai koso sure, wasureru koto wa dekinai.
I might regret it, but I can't forget it.
Gimon koso sure, sansei wa dekinai.
I may have doubts, but I cannot agree.
Practice
Grammar content sourced from hanabira.org.