If I gave my money to someone for donation but that person did not donate and kept it for himself without my knowing, will my donation be accepted by Allah (swt)?
You will be rewarded for your kind intention of giving in charity, but if you come to know that the charity money was not given to the deserving, you must take it back from him and make it reach to the deserving. Your donation will be accepted when it reaches to the deserving.
Wassalam.