こそ

こそ

1. 1

   it is ... that ...; precisely; in particular; definitely; for sure; only (when, after, because, etc.)

   助詞emphasizes preceding word or phrase
2. 2

   although; while; it is the case that ... but

   助詞as こそあれ, こそすれ, こそするが, etc.
3. 3

   it is precisely because ... that ...; only because ...

   助詞after conditional -ba form of verb
4. 4

   not at all; not in the slightest; absolutely not; never

   助詞after -nai stem of verb + ばformal or literary term