How do you know it was because you are foreign? I've been turned down a couple of times and I'm not foreign.
I guess it's a huge act of trust to open the door to a stranger based on the sound of a voice on the phone.
It probably doesn't take much to spook her, so, if your accent or your choice of words reminds her of someone she had a bad experience with, you might be out of luck.
As long as she comes straight out with it and says no and doesn't keep you hanging around....