I would want to answer this question by talking about the relationship of Marianne as defining sensibility to the kind of image of women that Wollstonecraft argues against in her essay. Wollstonecraft seems to argue for women to try and become more rational and defined by sense, rather than the image that men have of women, which is defined by sensibility. Note what Wollstonecraft argues for in her essay:
I wish to persuade women to endeavour to acquire strength, both of mind and body, and to convince them that the soft phrases, susceptibility of heart, delicacy of sentiment, and refinement of taste, are almost synonymous with epithets of weakness, and that those beings who are only the objects of pity and that kind of love, which has been termed its sister, will soon become objects of contempt.
It would be easy to see some of these adjectives as suitable for describing Marianne and her sudden, powerful attachment to Willoughby. Clearly, the relationship between these two texts would be that Wollstonecraft would argue that Marianne is a symbol of all that is wrong with women, and that women should strive to become more like Elinor: ruled by sense rather than sensibility.