からこそEmphasized because, Precisely because

Traditionally, the adverbial particle こそ is used to emphasize whatever noun (or noun phrase) it is attached to. However, when combined with the conjunction particle から, it focuses on emphasizing the 'reason' for something. This structure is very similar to phrases like 'precisely because (A)' in English.

からこそ is an expression that is primarily used after either verbs or nouns. In the case of nouns, the noun will need to be followed by the auxiliary verb だ, before からこそ is added.

With からこそ, there may be several reasons for why something is the way it is, but こそ will show that there is a 'foremost' reason that should be considered before anything else.