Changed battery with a new one but engine turns over but still won't start?

Hello, I'm Danny.

It sounds like you are having an issue with a failed in-tank electric fuel pump. Since you mentioned starter fluid starts the car then you should focus on the fuel pump. Here is a tutorial showing how to change an in-tank pump:

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

I've attached picture steps below on how to change the in-tank electric fuel pump on your Jetta. You will have to remove the seat cushion to gain access to the fuel pump via a metal access panel. Hope this helps and thanks for using 2CarPros.