They are prized, and relished. They become radiant, and zealous, and passionate, hot, devoted and dutiful. They set themselves to win the love of their master, and not unoften they succeed. Many then become the love slaves of love masters. They are kept as slaves, of course, for they are slaves; too, of course, as slaves, they are kept under perfect discipline. She, as other slaves, would not want it any other way. How could she, or any other slave, respect a master too weak to enforce discipline, too weak to get the whole slave from her? They are radiant. They are joyous in their collars.
To be sure, not all slaves are love slaves.
---Tribesmen of Gor, 13:

"I exist for you," she said, "and it is what I want, to please and serve you." She was much in love. She wanted to give all of herself to him, irreservedly, to hold nothing back, to live for him, and, if necessary, to die for him. It is the way of the female in love, for whom no service is too small, no sacrifice too great, offering herself selflessly as an oblation to the master."
--- Magicians of Gor, 27

"He took me by the hair and thrust my head down to the furs. "A man can truly love only that woman," he said, "who is truly his, who belongs to him. Otherwise he is only a part to a contract." "A woman," I said, "can love only that man to whom she truly belongs." "To whom do you truly belong, Slave?" he asked.
"To you, Master," I said.
"You please me, Slave Girl," he said.
---Slave Girl of Gor, 444

The point of the leash, of course, is seldom to hold or control a woman, for we are rational, and know we must obey, but rather to make it clear whose property she is, and to display her. Similarly, when a woman is leashed her status is made clear to her. Too it might be mentioned that the leash has a profoundly erotic effect upon the female, as its meaning, and its symbolism of her domination, is profoundly arousing to her.