Is working in a hotel's information desk, which requires recommending and booking restaurants and nightlife venues that feature dancing and singing, and having full knowledge of their details, in addition to knowing other entertainment venues like theaters and cinemas, considered unlawful, knowing that I do not frequent these places, and I am married with children and have no other source of income?

This act is forbidden due to its implication in promoting prohibitions. It falls under aiding in sin and transgression, which Allah has forbidden in His saying: (And cooperate in righteousness and piety, but do not cooperate in sin and aggression). He who points to evil is like its perpetrator. So, whoever calls to misguidance will bear the burden of sins similar to those who follow him, as stated in the Hadith: (And whoever calls to misguidance will bear the burden of sins similar to those who follow him). One must abandon this work and switch to a permissible one, for whoever gives up something for the sake of Allah, Allah will compensate him with something better. The provision of Allah is attained only through obedience to Him, as Allah Almighty says: (And whoever fears Allah - He will make for him a way out. And will provide for him from where he does not expect).