# My sister

"My dear" or "My darling". They are not actually brother and sister. See Song of Songs 4:9. 

# my bride

This Hebrew word can refer to a woman who is married or to one whom a man has arranged to become his son's wife. See Song of Songs 4:9.

# is a garden locked up

"is a garden that no one can enter." The garden is a metaphor for the woman, and the lock is a metaphor for her still being a virgin.

# a spring that is sealed

"a spring with a cover on it."