Is it permissible to spend on one's wife from the donation funds allocated to support new Muslims, knowing that she is one of the beneficiaries of this project?

If the charitable funds are designated to help new Muslims, and a woman among them is still in need, then do not cut off assistance from her unless she has been provided with financial support due to a lack of material means or her acceptance of marriage to you without requiring support. There is no blame on a husband for depriving his wife of something she has waived. Donations must be spent in accordance with the donors' conditions, and it is not permissible for the person in charge of collecting donations to take anything for himself except with the knowledge and permission of the donor.