Disclosure: I don't love love the use of the term "Jew-usurer" on the surface, but here, with the previous name-drop of King Ahasuerus, it is clear that Jane is referring to Esther 7. For those curious; usury can be simplified as a very old term for interest in the financial sense. The addition of "Jew" by Brontë was more to do with the Old Testament reference than with any ill-intentioned racism. In this situation, Jane was aligning herself with Esther, not bashing Judaism.