Aviendha

In The Wheel of Time, Aviendha of Bitter Waters sept of Taardad Aiel (clan), Aviendha for short, is an Aiel woman, former Maiden of the Spear, currently in training to be Wise One.

She is one of three women in love with Rand al'Thor, and also was the first (and so far the only) one of three to have sex with him. Rand feels the same towards her, however, he tries to deny this as he tries with other two, in fear that they will get hurt, if not by heart, then by body; Shadow is known to use efficient technique of breaking leading figures of Light by making their loved ones hurt (this technique is known to be used in turning Ingtar, Shienaran lord to Shadow or to make LTT suicide, for example). In this fear Rand might be correct, however, it is propably useless to struggle as Shadow already knows about his feelings.

Aviendha herself was trying to struggle against become Wise One; she didn't decide to become one, but Wise Ones did. She was Maiden of the Spear before, and she certainly wanted to keep so. She could channel, rather strongly actually, which propably was important factor in Wise Ones' decision.

As Maiden, she was with the group that took over the Stone of Tear, and when they got back to Aiel Waste, she was assigned to both spy Rand al'Thor and teach him Aiel culture. The spying part didn't quite work out as Rand was smarter than they expected, and the culture part got difficult as Aviendha started to realize she was falling in love and in struggle to this became quite intolerable. Still, she managed to teach Rand enough and at the same time fulfill her true meaning as Algorithm of the Wheel her set, to keep Rand somewhat sane with her love (that is of course just speculation, but then again, isn't everything).

As for her personality, to wetlander she seems like a typical Aiel (woman), fierce, strong, indepedent and so on; Aiel Wise Ones characterized her as 'headstrong'.

Update required!

Min Farshaw also had sex with Rand and in fact got to spend the most time with him. I can't remember which book this started in. In Winter's Heart, the latest book as of my writing, Elayne Trakand also got to sleep with him, but only because Min forced him to go see her, knowing that he was in love with all three of them.

More details on one matter: Aviendha struggled against her love for Rand because she was good friends with Elayne, who loved him first and so he "belonged to her." But the two eventually became First Sisters, which means they can't let a man come between them and therefore both have to marry him or neither. Elayne also considers herself a First Sister to Min, although they have not taken the vows, and is currently trying to get Min and Aviendha to become First Sisters also.

And yes, the Wise Ones require that all women who can channel become Wise Ones also (though women who can't channel can also choose to). Men who can channel, on the other hand, are expected to go into the Blight and kill as many Shadowspawn as possible before they get killed.