S. R. Faruqi:

The ambiguity of the verse is worth noting. To see a flower in the night can be a real event, and can also be a dream. Whenever at night, or in the night, he saw a flower, then at dawn, or the next day, there was a visit to the beloved. But 'to see the face' can be by chance; or rather, it can also be intentional-- that he devised the scheme that if in the night he would see a flower, then in the morning he would go and see the beloved as well.

The second line is the bearer of further ambiguity. One possibility is that he doesn't fall asleep at all, or else sleep comes but no dream is seen. Thus there's no possibility of seeing the flower. A second possibility is that in his agitation and anxiety over seeing the flower, sleep doesn't come to him. In any case, he doesn't see the flower, so in the morning it's also not possible for him to see the beloved's face.

An additional possibility is that the whole situation would be that of a dream. That is, he is longing to go to sleep in order to see a dream. And if there would be a dream, then it's possible that in it a flower too would be visible. And the interpretation of it would be that the next day he would see the beloved's face. But because of this agitation, sleep does not come. It often happens like that-- someone wants to go to sleep, but sleep doesn't come.

Then, logo;N kaa saa ;xvaab nah ho too is an interesting phrase-- that other people do not see dreams the way we do, nor is the interpretation of their dreams like that of our dreams. Or, other people hardly sleep and wake the way we do! Our sleeplessness, or the way that dreams remain far from us, is in our fate alone. It's a verse of 'mood'.

FWP:

SETS == IDIOMS
MOTIFS == DREAMS; SCRIPT EFFECTS
NAMES
TERMS == AMBIGUITY

The second line also offers the enjoyable script effect of the havaa hu))aa , which could perfectly well be read, on a first encounter, as hu))aa hu))aa , since the second verb might go on to apply to a following clause. (If you're not so familiar with Urdu script, note that the spelling of the verb hu))aa is irregular.)

The speaker's sleep has, idiomatically, 'vanished' [havaa ho jaanaa]-- or else it has, literally, turned into havaa , with its rich array of possible meanings (see the definitions above). Then the rest of the second line takes elegant advantage of the possibilities of the future subjunctive. Here are some ways in which it could be read:

='Our sleep/dream would not be like the sleep/dream of [other] people'-- because the speaker can't sleep at all, or because his dreams have a special visionary efficacy.

='Our [idea of] sleep/dream might not be like the [idea of] sleep/dream of [other] people'-- because the speaker might have a special notion of what it means to 'sleep/dream', and other people might have no sense of such an inner reality at all.

='May our sleep/dream not be like the sleep/dream of [other] people!'-- may others not sleep the way the speaker does! Because no one would wish such dire sleeplessness on others; or else because the lover wouldn't wish others to share his vision of the beloved.