Did Rodolphus think she was Bellatrix at times? Or did he just forget sometimes and misremember conversations? Based on what Hermione knew about Bellatrix, she had a hard time believing that she would speak so openly about a world without Lord Voldemort. She had been in a sick, demented sort of love with their mutual master. But, she had to remind herself that the public persona one had didn't always match who they were in private. She knew that firsthand. Even in the most difficult and unhappy years of her marriage, both she and Antonin felt safe enough to come home and remove the mask they had to wear. Perhaps Bellatrix was more like her than she realized.