Perhaps they should add "sisu" to English dictionaties. After all, you will find "chutzpah" in English, Hindi, and Urdu books because we do not have such a short way to describe something we often see.
After having seen the various meanings and descriptions, I've just come to translate it as ''perseverance''.
As every grandma is :)
Sisu in English, I guess, would be gut or spirit, but otherwise it should not be translated as "sisu" in English
i think because sisu can't really be translated exactly.
This would be the reason why it isn't translated