こんにちは!
ご質問ありがとうございます。
ご質問について、いくつか言い方が考えられますが、例えば、
Most people think she won't change like 99% of her is set in stone. They ask me why I bother caring for her. But I believe in that remaining 1%. She's the woman I once saw potential in, and no matter what anyone says, I'm convinced that only I can help her change and save her. I have faith that one day she'll realize her mistakes on her own.
とするのはいかがでしょうか。
役に立ちそうな単語とフレーズ
set in stone 不変である
bother doing あえて・わざわざする
care for ~のことを思いやりを持って考える、~に気を使う
see potential in 人に可能性を見いだす
no matter what anyone says 誰が何と言おうと
have faith that という信念を持っている
参考になれば幸いです。