In part 2, what does the author mean by the “sinister meaning of the assurance” and the “awful confirmation of her fears”? How do the words “sinister” and “awful” contribute to the tone of the text

The use of sinister indicates an omen or something evil. By using the word sinister, the author brings up the foreshadowing from previous pages when the White's learned the fate of the previous owner of the monkey's paw. The "awful confirmation" tells the reader that Mrs. White's worst possible fear has come to fruition.