I'm not talking about the (in)famous quest here, I am simply talking about the person: Lord K'avar, Castle Sentinel, first door to the right. It is a little appreciated fact that his quests pay a lot better than others. At level 2, when the guilds or the average noble pay barely a hundred, he might give you sixteen hundred; at higher levels, several thousand. Besides, there is always a small stash at his place, on the floor of the small chamber opposite his mistress, Rholp-e, who, by the way, will speak only to women; and his rooms are far away enough from the guards for you to rest there.
Unfortunately, reputation in Sentinel is a strange thing. You can get it high without ever setting foot there, yet the people in court might still refuse even to talk to you. And you might have a high reputation with Lord K'avar and still not get a job from him. In this case, do a few quests for Lord Vhosek, the tall guy in black in the great hall. That usually works.