〜こそ
An emphatic particle that singles out the word before it: this one and no other, precisely this. Attaches to a noun, usually in place of は or を, though こそが and こそは also occur. Used in both speech and writing.
N + こそ（は・を は落ちる。「こそが」「こそは」の形も可）／ V-て + こそ