"Believing That You Are Mine Forever" signifies the depth of the emotional connection between the speaker and the person they love. It implies a strong sense of ownership and commitment to the relationship.
"Is What Makes Me Get Up in the Mornings" emphasizes that this belief provides the speaker with a reason to face each day with enthusiasm and motivation. It signifies that the love and connection they share give them purpose and drive.
In essence, this quote beautifully captures the transformative and motivating nature of love, where the belief in a lifelong commitment can infuse life with meaning and a sense of purpose, encouraging the speaker to greet each day with optimism and hope.