Complex sentence: Jane, believing that Bingley no longer loves her, accepts her mother's advice to marry Collins, but as the newlyweds drive from the church the expressions on Jane's and Bingley's faces express deep disappointment.
Split into simpler sentences: Jane, believing Bingley no longer loves her, accepts her mother's advice to attract and marry Collins. But as the newlyweds drive from the church, the expressions on the faces of herself and Bingley both express deep disappointment.