The fact is, that you'll never know exactly what she's thinking or aware of. You can only know what someone shares with you, and a manipulator will never admit that they're manipulating you and will always play the innocent/victim card if accused of it.

So go with your instinct and remember that she will keep trying to tie herself to you. If she talks about the bus pass again, point out what a great idea that is because then she doesn't have to worry about car payments and what a great way to help the environment! Turn everything you can into a positive. If she brings out the fact that she'll need things she somehow can't carry on her own.. then point out that you'd be able to help her based around your own schedule.