O que significa We are gonna be ending up ?

See a translation

It has two meanings:
In the end, some action will need to happen, even if you try to prevent it.

or

If you keep doing something, the end result will (usually) be bad

Ex.
~We will end up dating each other, so let's start now.
~You're gonna end up hating ice cream if you eat it every day.
~I'll end up cleaning the whole store by myself anyway, so why ask for help now?
~If you try to hurt them, you'll end up in jail.

I think when we use it, it generally has a negative meaning, but you can use it with a positive meaning too (it is just a little rare to think of the positive situation with that meaning)

Let me know if you need more help!