incorrigible

1. ADJ If you tell someone they are incorrigible, you are saying, often in a humorous way, that they have faults that will never change. 屡教不改的

"Sunita, you are incorrigible!" he said. “苏尼塔，你真是屡教不改啊！”，他说道。

Gamblers are incorrigible optimists. 嗜赌的人是死不悔改的乐天派。