You chose the countess to convince Arabella that romances are not reality
While in the novel, Arabella is converted after a conversation with a doctor, Lennox apparently considered having the countess character convince Arabella instead. During the substantial changes to Lennox's ending as advised by Samuel Johnson and Samuel Richardson, that plot point was changed to the doctor being the one to persuade her instead. The countess, unlike the doctor, has read the same romances as Arabella and as such has an understanding of their appeal, which makes your choice to have her be the one to convince her quite fitting. Women at the time expressed frustration with the novel's actual ending -- "the chosen cure of
Arabella via a conversation with a Johnsonian cleric was a matter that did vex at least two professional women writers who read the novel in the ensuing decades of the Georgian period" (Wyett 14). Those female writers, according to Wyett, complained that the plot aligned with "patriarchal power structures" with its ending (Wyett 14). Langbauer argues that "the Doctor comes out of nowhere and his cure of Arabella jars with the rest of the story rather than smoothly resolving it" (Langbauer 73). By having another woman convince Arabella, your choice shifts the dynamic of the novel away from patriarchal norms and gives the Countess's character a purpose in the novel rather than seeming to be introduced for no reason.
Arabella via a conversation with a Johnsonian cleric was a matter that did vex at least two professional women writers who read the novel in the ensuing decades of the Georgian period" (Wyett 14). Those female writers, according to Wyett, complained that the plot aligned with "patriarchal power structures" with its ending (Wyett 14). Langbauer argues that "the Doctor comes out of nowhere and his cure of Arabella jars with the rest of the story rather than smoothly resolving it" (Langbauer 73). By having another woman convince Arabella, your choice shifts the dynamic of the novel away from patriarchal norms and gives the Countess's character a purpose in the novel rather than seeming to be introduced for no reason.