"Ens bil er ens egen."
Translation:One's car is one's own.
Egen is not pronounced correctly. Google Translate does it as it should. https://translate.google.dk/?hl=datab=wT#da/en/egen
I am not a language person by trade, but I am a dane. I would say that it definitely is not an idiom, but rather inappropriate sentence for learning a language I think. That sentence is quite quirky, even in both languages in question, and might only lead to unnecessary confusion.
I guess the author thinks that a sentence with the danish word "ens" should be used in a context where it does not mean equal.