These words could be 1) a reference to the literal royal palace where the king lived or 2) a metonym for the family, the royal line of the kings of Judah, that lived in the house. Alternate translation: "the royal dynasty of Judah" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Possible meanings are 1) "You are as beautiful as Gilead or the summit of Lebanon" or 2) "You give me as much pleasure as Gilead or the summit of Lebanon." (See: [[rc://en/ta/man/translate/figs-simile]])
What was formerly beautiful is said to become bare and deserted. Alternate translation: "cause you to become empty like the desert" (See: [[rc://en/ta/man/translate/figs-metaphor]])