Kamasutra 6.1.6

6.1.6

na cānupāyenārthān sādhayed āyatisaṃrakṣaṇārtham/

By having intercourse with men courtezans obtain sexual pleasure as well as their own maintenance. Now when a courtezan takes up with a man from love, the action is natural; but when she resorts to him for the purpose of getting money, her action is artificial or forced. Even in this latter case, however, she should conduct herself as if her love were indeed natural, because men repose their confidence on those women who apparently love them. In making known her love to the man, she should show an entire freedom from avarice, and for the sake of her future credit she should abstain from acquiring money from him by unlawful means.