Dairihill is a Bosmer noble and the personal steward of Countess Millona Umbranox of Anvil. She is trying to get her cousin promoted to the position of captain of the guard in Anvil. She seems to be upset by the Thieves Guild interfering with the recommendation.
S'Krivva of the Thieves Guild is very suspicious of her, even saying: "Dairihill cannot be trusted. You must deliver the letter to Lady Umbranox in person." she also says "The letter is currently in steward Dairihill's desk. She has lied to Lady Umbranox, telling her that the letter has yet to arrive."