What is the tone of this novel?

More than in any of Austen's other novels, there is an autumnal, melancholy, plaintive tone through much of this last completed work. Unlike in Austen's earlier novels—which capture the heroines right on the brink of adulthood, aged roughy eighteen to twenty-two—Anne Elliot, at twenty-seven, is past her prime. Her bloom is off. She lost her true love, Captain Wentworth, years ago, when her mentor, Lady Russell, persuaded her to break off the engagement because of his uncertain financial situation.
As the novel opens, Anne lives with patience, level-headedness, and resignation, but with a sense that the best in life has passed her by. She solaces herself with helping others, reading poetry, and taking walks but is not highly regarded by her self-absorbed father and sisters. She doesn't expect ever to marry. She regrets what could have been.
It is against this backdrop that Captain Wentworth reappears, turning this into a novel about second chances, about people older, sadder, and wiser finding fulfillment.