"I am stranded in a strange place with limited foreign currency and no memory of how I arrived. I would not trust my own brother approaching me under these circumstances, much less a stranger."

Granted, trusting Zuko usually proved foolish, but he had, last time, not wholly disappointed her. He'd made the right decision, ultimately, at least. Still, this man didn't need to know about her family matters, so the remark could stand on its own.