Complex sentence: At the novel's end, she returns to the Elias-Clark building to discuss a position at one of the company's other magazines and sees Miranda's new junior assistant, who looks as harried and put-upon as she once did.
Split into simpler sentences: At the novel's end, she is returning to the Elias-Clark building to discuss a position at one of the company's other magazines. She sees a girl, who she realizes is in fact Miranda's new junior assistant, who looks as harried and put-upon as she once did.