This is pretty long, do you say this fully or is it one or the other? Also what does it mean? では・じゃ｝ありません


I just read this lesson on imabi and i'm confused.

"To make a polite negative phrase, you have two options. You can simply add です
to ～ない. When you do this, you aren't actually saying "is" again. In this case,
です's meaning is just showing politeness. Or, you can use ～｛では・じゃ｝ありません. If you
remember from Lesson 8 that だ comes from である and that it will be important to
know this later on, the time is now. Polite conjugations using it are "more
polite" than just using です. So, they are best used with people whom you should
show more respect."




It means you can either use `ではありません` or `じゃありません` to express a negative
polite phrase.

So, `私は医者ではありません` and `私は医者じゃありません` are both fine.

