"She is still okay."
Translation:Cô ấy vẫn ổn.
We don't have the same thing with "to be" in Vietnamese. In Vietnamese the sentence is perfectly OK with just "subject + adjective".
For example: "I am fine" means "Tôi khỏe" (Tôi = I, khỏe = fine).
Adding the translation of to be in Vietnamese sentences most of the time will make it weird and unnatural.