Complex sentence: With a letter of introduction from Sherwood Anderson, Hemingway secured an invitation to tea for himself and his wife Hadley, who found Dorothy's manners to be intimidating, and he considered their apartment to be as "poor as Gertrude Stein's studio was rich".
Split into simpler sentences: With a letter of introduction from Sherwood Anderson, Hemingway secured an invitation to tea for himself and his wife Hadley. She found Dorothy's manners to be intimidating, and he considered their apartment to be as "poor as Gertrude Stein's studio was rich".