If you are planning to confide a secret to someone and dream of castration, it serves as a warning. This dream signals your subconscious mind that acting based on your trust may not be wise. It indicates caution regarding your relationships, so be careful and reconsider your decisions.
From Imam Muhammad Ibn Seerin's Dictionary of Dreams According to Islamic Inner Traditions â entry "Castration" (page 71).
Ifone intends to bank something with someone as a trust or to confide a secret with someone, then ifhe witnesses a case of castration in a dream, he should immediately halt that intention, or cancel such arrangement. If one sees
7:.:! himself castrated in his dream, it means that he declines to testifying to the truth. Ifone finds that he became castrated, or ifhe does so to himself in a dream, it means that he will be inflicted with humiliation and submission to someone's command. If one meets a castrated person who is unknown to him and who has a dignified look and speaks words of wisdom in the dream, it means that he has met an angle who is conveying glad tidings or bringing a warning from his Lord. Ifhe recognizes the castrated person in his dream, it means that he has met with an acquaintance of his. Seeing oneself castrated in a dream also means increase in one's devotion and guarding of his chastity. Castration in a dream also means negation of favors, loss of one's family or children, or it may imply absence of mannerism, choosing to satisfy one's personal comfort over the interests of others, and it represents evil intent or hypocrisy. (Also see Impotence)
Note: Islamic dream interpretation depends on the dreamer's circumstances and state. This is a general guide drawn directly from the source book.