S. R. Faruqi:

The opening-verse is by way of introduction, but it's also not entirely lacking in pleasure. Between baariik and ;xayaal is the connection of a zila. Among kamar , baal , dil , haath there's wordplay.

The second line has two meanings. One is that we would assume dil to be vocative: Oh heart, if that thing (the beloved's waist) would not come to hand, why even think about it? The second is that we would assume dil to be the beloved's heart: When this is the condition of the waist, then why even think about the heart that would not come to hand?

One more meaning is that when the waist itself is more delicate than a hair, if the heart would not come to hand, then how will you even think about it?

FWP:

SETS == KYA
MOTIFS == [BELOVED HAS NO WAIST]
NAMES
TERMS == WORDPLAY

That second line makes such an ambiguous use of the 'kya effect' that it feels almost opaque. 'What is the thought of/about that one?!' is surely as idiomatically multivalent as it's possible to get within the space of five words.

The best way to enjoy the verse is to follow the guidance of the first line and read the kyaa hai as an emphatic form of the comparative. In the first line, by comparison to her waist, a hair has much less delicacy/thinness. Thus in the second line, if her (inaccessible) heart has no graspability, by comparison (the thought of) her waist has even less graspability. (If the lover can't get hold of her relatively tangible heart, how can he ever expect, or even imagine, that he could get hold of her wildly intangible waist?)