Is it permissible to market and sell wedding and evening dresses wholesale to stores to improve one's financial situation?

The basic ruling is that it is permissible to sell these clothes, unless their predominant use is for unlawful display (tabarruj). In that case, it is not permissible to trade in them, as that would be assisting in sin. Allah Almighty says: (And cooperate in righteousness and piety, but do not cooperate in sin and aggression).