One of the female characters you can marry in Skyrim is Brelin Marion. You will meet this girl in the College of Winterhold. Before you marry her, you will need to fulfill several conditions. You will learn how to do this from this material.
Acquaintance with Brelina
The girl lives in the College of Mages of Winterhold. The first time you meet her when completing the quest "First Lessons". But before making friends with Brelina, you will need to complete the quest "In the Ruins of Saartal." To do this, go to the Nordic ruins located south of Winterhold, and enter them along with other mage students.
After the introductory part, Tolfdir will send you to help Arnel Hein. He will ask to find four magic items. When you take the last amulet, you will fall into the trap. To get out of it, put on an artifact and use the “Destruction” school spell on the wall. Next you have to find in the ruins of the "eye of Magnus." This magical artifact is hidden at the end of the location, and on the way to it you will have to engage in battle with the Draggers. After completing the quest, you will become a full member of the College and will be able to receive tasks from Brelin Marion.
Fulfillment of the request
To start the quest “Homework”, go to the Support Room and talk with the girl. She will ask you to become an “experimental rabbit” in her magical experiments. If you want to marry a dunmer, then agree. Brelina will cast a spell on you, after which everything around will turn greenish. This effect will last about four hours of playing time.
When the world gets the usual colors, return to the sorceress. She will again ask for a favor and after consent she will begin to cast spells on you. After the first you will turn into a cow, and the second will make you a horse. The third spell will turn into a dog. And only the last, fourth, will return the usual appearance. After that, Brelina will thank, apologize for the inconvenience, and offer her services as a companion. Now you can marry a girl. Read about what you need in the next chapter.
How to marry a girl
To marry Brelina, you need to get the amulet of Mary. You can find this artifact in a random Skyrim chest, or buy it for 200 gold from the priest Maramal. You will find the character in the temple of Mary Riften. In order for the amulet to work, it is important to talk with the priest about marriage. After that, put on the artifact and go to Brelina. When talking with her, a new answer will appear, and you can offer the girl to marry.
After Marion agrees, go with her to Riften and go through the wedding ceremony in the temple of Mary. When you become husband and wife, Brelina will ask where you will live with her. Choose any of your houses, and the girl will go there.