Is the young man who suffers from obsessive thoughts about the Divine Self and fears of illness and crowds sinful for concealing this from his fiancée, and must he inform her before marriage?

The defect that must be mentioned to the fiancée is one by which the marriage could be annulled if found in the husband. Any matter that repels the other party and prevents the fulfillment of the purpose of marriage necessitates the option (of annulment). However, involuntary fears generally do not repel souls or prevent the purpose of marriage, and therefore, they do not need to be mentioned to the fiancée.