2. You are more beautiful than butterflies.
Your sunflower brings me brilliant sunshine. (Sunflower is appositive)
I promise you the sky and hope, will you return my three happy days as a gift?
You are like a blooming flower in my heart.
6. I'm just waiting for the angel to come.
7. You are a beating note in my heart.
8. Your voice is like that of a piano.
Because of the differences in grammar and semantics between Chinese and English, I made some changes, but the basic intention remained unchanged.
I'm tired of translation. I hope it can be adopted:-D.