1.It's OK. / That's OK. 没事儿!
2.No problem at all. 完全不是什么问题。
3.Forget it. / Don't take it to heart. / Never mind. / Don't worry. 别往心里去。别在意。
4.It doesn't matter. 不要紧。
5.Why? What's wrong? 为什么这么说?怎么了?
6.That wasn't about you. / It's not your fault. 不是你的错。不关你的事。
7.Don't blame yourself. 不要责怪你自己。