Volkswagen Jetta is a very good option.
This car is a driver's delight and you won't regret it.
Maintenance should cost around 15-20k yearly. That's the norm with this VW and SKODA.
If it's a Pre 2010 model, then it will be one with 1.9 PD engine mated to 6 Speed DSG, which is very reliable.
Post 2010, the PD engine was discontinued in favour of more advanced 2.0 TDI CR engine. This was big improvement especially in terms of refinement. The old Jetta did not have Highline variant at all, i am guessing it's the Comfortline which you have seen. Again standard features across variants makes it easier to get one without thinking too much.
Price quoted is a bit high IMO
. It should be around 5-5.5 at max. It's an exhausted product so, you can ask for lower price.
Overall, Get that car if record is clean and if you are happy with it. It's an excellent car.