Is it permissible to give a sum specifically designated for charity to another person to donate on my behalf, knowing that my intention is a mixture of seeking reward and desiring to marry his daughter?

The resolve to donate some money to help someone marry should be carried out. There is no objection to appointing someone to do so on behalf of the donor, even if the donor wishes to marry the recipient's daughter. However, if the appointment is for a purely worldly purpose, such as gaining favor or admiration, it is not permissible. In such a case, the donor should appoint someone else or undertake the matter himself to ensure sincerity, as Allah Almighty says: "And they were not commanded except to worship Allah, [being] sincere to Him in religion, inclining to truth, and to establish prayer and to give zakah. And that is the correct religion." One can also seek assistance from specialized charitable organizations.