YOU SAID:
Sensei wa kibishii desu
INTO JAPANESE
先生はきびしいです
BACK INTO ENGLISH
The teacher is severe
INTO JAPANESE
先生は厳しいです
BACK INTO ENGLISH
Teacher is tough
INTO JAPANESE
先生は大変です
BACK INTO ENGLISH
Teacher is hard
INTO JAPANESE
先生は難しい
BACK INTO ENGLISH
Teacher is difficult
INTO JAPANESE
先生は難しい
BACK INTO ENGLISH
Teacher is difficult
That didn't even make that much sense in English.