Express the emphasis on the reason; 'precisely because', 'it is precisely because'.
Long explanation:
The ~からこそ grammar point is used to emphasize on the reason or cause of a situation, usually indicating that the effect or outcome is surprising, unexpected, or especially significant. It can be translated as 'precisely because' or 'it is precisely because' in English. It attaches to the end of a clause that states the causal or motivational factor.