In the dream you described about marriage, feeling both frightening and peaceful, there are several symbolic elements to consider within Islamic dream interpretation.

Key Symbols:

1. Marriage (Nikah - نكاح): In dreams, marriage can symbolize union, commitment, or a new beginning. It often reflects personal or spiritual transformation.
2. Mixed Emotions (Fear and Peace): Feeling fear might indicate an internal struggle or apprehension about a significant change or decision. Peace could symbolize acceptance or assurance from Allah.

Traditional Interpretations:

• Marriage in Dreams: It is often seen as a sign of a new phase in life, personal development, or a significant commitment. This could be related to one's spiritual journey, personal goals, or actual life events related to relationships.
• Dual Emotions: Experiencing both fear and peace might suggest that while there is anxiety about the unknown future, there is also a deep-seated trust in Allah's plan.

Personal Reflection:

Given your mixture of emotions, this dream may reflect an inner conflict where you are faced with decisions that could lead to significant change—perhaps in your personal life, career, or spiritual path. The peacefulness suggests trust in Allah's guidance.

Spiritual Reflection:

It might be beneficial to turn towards prayer and seeking counsel through Istikhara (صلاة الاستخارة) for guidance. Trust in Allah’s wisdom, for He knows what is best for you even when the path seems unclear.

Consider this dream as an invitation to evaluate any upcoming decisions or transformations in your life and to ensure they align with your values and faith. Always remember, "And whoever fears Allah—He will make for him a way out. And will provide for him from where he does not expect" (Qur’an 65:2-3).

May this dream bring you closer to understanding the paths Allah has chosen for you.