Why does Islamic society's view of a girl who has erred differ from its view of a boy who has erred, even though they share the same mistake? What is the Sharia ruling on a husband who denies his past mistakes committed before marriage, and is that considered deceit, similar to a girl's denial?

Islam does not differentiate between men and women in terms of religious obligations and penalties. If a penalty is due, it is imposed on both without discrimination, as is the case in the verses concerning adultery and theft. Whoever commits a sin before marriage must repent and conceal it, and this is not considered deception.