Instructions
Play as a human female Warden. Alistair is heterosexual and will not respond to the advances of a male Warden.
Raise Alistair's Approval Rating to the highest level. Approval can be gained by making decisions Alistair approves of while he is in your party. He is very morally upright, and speaks out often about the choices you make. Typically, if you choose the "good" option in most situations, you will gain his approval.
Give Alistair gifts. Giving gifts gains you approval with the receiver. Like all characters, Alistair has a number of gifts he prefers, gifts that net you the greatest amount of approval from him. They are Alistair's mother's amulet, the black runestone, Duncan's shield, the Joining Chalice, the onyx demon statuette, the small carved statuette, the stone dragon statuette, the stone warrior statuette and the white runestone.
Speak with Alistar often while in camp. Try to be sympathetic to him. Never mock him, and take the kinder speech options.
Choose the correct options at the Landsmeet. Do not allow Alistair to marry Anora. Make him king. Have Loghain executed. If you played as a human female, you can offer to marry Alistair and become queen. If you played as an elven or a dwarven or a mage female, you can't marry him, but you can be his mistress.
Accept Morrigan's offer after the Landsmeet. If you reject it, either your player character or Alistair will die in the final battle.
Leave Alistair out of the party you take to face the Archdemon. If you take him, he will die at the penultimate moment regardless of whether you accepted Morrigan's offer. You will marry Alistair after the Archdemon is killed.