厳しい, 酷しい, きびしい
1. severe, strict, rigid, unsparing, relentless
2. hard (to do), difficult, tricky
3. intense (e.g. cold), harsh (weather), inclement
練習がどんなに厳しくても、彼女は決して泣かなかった。
のです, んです
Expression, の and ん add emphasis
the expectation is that ..., the reason is that ..., the fact is that ..., the explanation is that ..., it is that ...
お借りした車の調子が悪いのですが。