And never the laugh has followed the sigh,
since you from your land were brought.
Ah . . . it's starting to make sense. Astair is a not a native-born Midianite. She is a foreigner who was "brought" to Midian, no doubt against her will.
And ever since she first arrived, she's moped around the palace, sighing heavily, and she never laughs. Jeez, with that attitude, I wonder how she ever got the king to fall in love with her!
The king has asked her why she's sad, but I think, deep down, he already knows the answer: Astair misses her homeland. (Gosh, I hope he didn't destroy her homeland completely!)