Should the prayer be repeated if the worshiper forgot the intention, coupled with excessive doubt?

Intention is a condition for the validity of prayer. It is a heartfelt purpose and action, and its place is the heart. The idea of prayer without intention is very far-fetched; for whoever performs ablution and goes to the mosque awaiting prayer has indeed intended it. Any doubt about the intention after that is usually a whisper from Satan that should not be heeded. If doubts about purity or prayer become frequent, they are of no consequence.