Faṣl does not always indicate complete disjunction. Here the two clauses are closely connected: the first states Salmā’s belief and the second provides the poet’s verdict on that very belief. Their subject matter is shared.
CaseWhy coordination is omitted
Complete disjunctionNo suitable connection, or an incompatible change of clause type
Quasi-complete disjunctionConnection exists but wāw risks unintended attachment or meaning
Quasi-complete connectionThe second clause answers an implied question raised by the first
The diagnostic question is: What unintended interpretation becomes plausible if wāw is inserted?