Romance (Origins)

In Dragon Age: Origins, Wardens of either gender and any race can pursue a heterosexual or homosexual romance. There are four companions who can be romanced. Morrigan, a "Witch of the Wilds", and Alistair, a young and sarcastic Grey Warden, are the heterosexual options. Leliana, a sister at a local chantry with a dark past and Zevran, an Antivan assassin, are bisexual romance options. No other companions can be romanced.

Initiation
High approval and correct dialogue choices help to initiate romances.

Alistair
Alistair is only romancable as a female player. Take a joking route with Alistair as often as possible, so long as you are not laughing at him or his romantic gestures. Humorous responses versus serious ones will often lead to a bigger approval bonus. Dialog options that make him feel wanted or needed gain lots of approval; avoid insulting Duncan or the Grey Wardens, as well as being rude to him. Agree with him as much as possible. Certain dialog choices that are particularly cruel will end the relationship--however, most have the option to apologize for: as long as there are still conversations that will initiate a romance, it is possible to rekindle the relationship. Once Moderate Approval has been reached, he will give you his gift; at Major Approval he will confess he cares for you a great deal and kiss you; at Massive Approval, with his personal quest completed, he will ask to spend the night with you.

Morrigan
Morrigan is only romancable as a male player. It is important to remember that Morrigan is very set in her ways. If pursuing a romance with her, it is advised that you agree with her philosophy of "survival of the fittest". The Witch can be easily offended at first and so you should choose your words carefully. She is also an apostate, and as such, has very negative views toward the Chantry and toward Templars. She will often say that she doesn't wish for love, and you should agree with Morrigan without insulting her. At Moderate Approval, she will ask you to sleep with her. At Major Approval she will give you her gift. At Massive Approval, with the completion of her personal quest, she will confess her feelings.

Zevran
Be accepting of Zevran's past, and often sympathetic when you can. If the dialog option is present, make it clear you wish for Zevran to do what he thinks is best for him. Do not be negative of his occupation as an assassin, his sexuality, or his views on casual sex; it is often best to agree with him. At Moderate Approval he will make it clear he wishes to romance you. At Major Approval he will ask you to his tent. At Massive Approval, and his personal quest completed, he will give you his gift and express his feelings.

Leliana
Leliana is romancable to male and female characters; however, female character must express some sort of romantic intention before she will make her sexuality apparent--if the first camp conversation ends without a initiating romance, female characters must wait until her personal quest has been completed to romance her again. Leliana is religious, and wishes for you to agree with her religious views. She wishes for you to treat her kindly and romantically, without objectifying her.

Love
Personal quests will be triggered as long as party members accompany the warden and have high enough approval. Completing the personal quest will likely result in significant gains of approval. In the case of Alistair and Leliana, certain dialogue options following the personal quest offer advice which will 'harden' the character, making them less judgmental of actions which they find disagreeable. Party members may express a feeling of love before the personal quests are completed. The personal quests are:
 * Flemeth's Real Grimoire
 * Alistair's Family
 * Leliana's Past
 * Defeating Taliesin (Zevran)

Achievements
When the Warden spends the night with a romantic partner achievements are unlocked.
 * Sharing the night with Morrigan unlocks the "Witch Gone Wild" achievement.
 * Sharing the night with Alistair unlocks the "First Knight" achievement.
 * Sharing the night with Leliana unlocks the "Wine, Woman, and Song" achievement.
 * Sharing the night with Zevran unlocks the "Easy Lover" achievement.
 * Sharing the night with all romance options unlocks the "Hopelessly Romantic" achievement.

Romantic Quotes

 * "We shall make this last night together something to remember." Morrigan
 * "Maker's breath, but you're beautiful. I am a lucky man." Alistair
 * "I walked where the Maker led me and he has rewarded me for my faith. I found you." Leliana
 * "In truth, for the chance to be by your side, I'd storm the Dark City itself. Never doubt it." Zevran

Other Encounters
As well as the fully fledged romance options, The Warden can engage in brief sexual encounters and romances throughout the game.
 * Iona (Human Noble Origin only)
 * Dairren (Human Noble Origin only)
 * Mardy (Males using the Dwarf Noble Origin only)
 * Teli (Males using the Dwarf Noble Origin only) *threesome with Mardy only
 * Gorim (Females using the Dwarf Noble Origin only)
 * Isabela (If in a romance with Alistair (hardened), Leliana, or Zevran, Isabela will engage in a threesome. You can also have a foursome if you have Zevran and Leliana, if she is hardened)
 * Cammen (located in Dalish Camp)
 * Gheyna (located in Dalish Camp)
 * Prostitutes at The Pearl
 * The Desire Demon that has possessed Connor (only if the Warden is a mage and chooses to enter the Fade to confront the demon in person)

Awakening
According to the FAQ romances do not carry forward in Awakening, because you are away from your previous life fighting a new threat. Also there are no romances options available in Awakening. The story is focused more on the mission at hand and the new threat to Ferelden.