She remembered her first visit to Ron's house when Rabastan just randomly showed up at the front door while she was there. It had been difficult to believe him when he assured her that it was an awful coincidence. She didn't believe in those. Most of her reason for going back the next day was to test him. If Rabastan dropped by again, she would've never believed another word he said. Ron had plenty of opportunity to warn his mentor that she was there. The fact that he didn't helped her relax. Maybe there really was more of her old friend still there than she knew.