To reassure your boyfriend, convey emotional support through empathy and validation. Show practical reassurance with acts of kindness, presence, and reliability. Encourage open communication by actively listening and using reassuring language. Express verbal support through meaningful phrases that convey trust, care, and understanding. Foster a positive relationship environment by cultivating personal qualities like supportiveness and warmth. Remember that trust, commitment, and intimacy are crucial foundations for building reassurance and fostering a strong and lasting connection.