When the Supreme Personality of Godhead assumed the form of the beautiful woman Mohini-murti, the demons were certainly captivated, but the demigods present were not. In other words, those who maintain a demoniac mentality are bewildered by the beauty of a woman, but those who are advanced in Krsna consciousness, or even those on the platform of goodness, are not bewildered. The Supreme Personality of Godhead knew that because Lord Siva is not an ordinary person, he cannot be bewildered even by the most beautiful woman. Cupid himself tried to invoke Lord Sivas lusty desires in the presence of Parvati, but Lord Siva was never agitated. Rather, the blazing fire from Lord Sivas eyes turned Cupid to ashes. Therefore, Lord Visnu had to think twice about what kind of beautiful form would bewilder even Lord Siva. Consequently He was smiling gravely, as stated in the previous verse (prahasya bhava-gambhiram). A beautiful woman generally cannot induce Lord Siva to be lusty, but Lord Visnu was considering whether there was any form of woman who could enchant him.