Notice! You can complete this mission only after finishing Retaking Thirsk!
Meet with Hilund in Thirsk Hall and talk with her about hunting. The woman will then ask you to bring her 50 Riekling Spears. Though such an amount might seem astonishing, in reality you shouldn't have any problems with obtaining it. Just head to one of the many Riekling seats (e.g. Benkongerike or Frossel), kill the enemies and take their gear. If that's not enough, you can take a look into the Riekling huts - spears are a valuable loot there.
After obtaining the proper amount of spears, return to the quest giver and collect your gold reward (depending on your level). I you have the Amulet of Mara, you will be able to marry her (both homo and heterosexuals).