The answer is: That Jane values virtue and justice over wealth.
An allusion is an indirect or passing reference to something or someone. In the excerpt from "Jane Eyre," by Charlotte Brontë, Jane mentions Persian King Ahasuerus, who is associated in history for his concern over Jewish territory. In that respect, she claims she does not wish to invest in land like Ahasuerus, and considers that having Rochester's confidence is more valuable than his property.