What are the signs of accepted charity, and is joy in performing it an indication of acceptance, and does the fear of non-acceptance prevent it?

The feeling of fear that charity might not be accepted does not prevent its acceptance. Rather, it is a good quality of the believers who hasten to good deeds, as Allah the Almighty stated in Surat Al-Mu’minun: (And those who give what they give while their hearts are trembling because they know that they will return to their Lord It is those who hasten to good deeds, and they are the foremost in them). Commentators explain the verse to mean that believers give charity while fearing it might not be accepted, out of apprehension of shortcoming. As for joy at giving charity, there is no evidence to suggest it is a sign of acceptance. However, a Muslim's joy at being granted success in obedience is a sign of faith, as long as it does not reach the blameworthy state of self-admiration.