Breakdown of Sono frastornato e non so che questo sconosciuto sia il medico.
essere
to be
e
and
questo
this (masculine)
non
not
Questions & Answers about Sono frastornato e non so che questo sconosciuto sia il medico.
Why is sia used here instead of è?
The phrase non so che (I do not know that) is a negative declaration of knowledge. In Italian, stating that you don't know something introduces a layer of doubt, ignorance, or subjective perception into the dependent clause, which triggers the subjunctive. If it were a positive statement like so che (I know that), you would use the indicative è.
Does using the subjunctive sia mean the stranger isn't actually the doctor?
Not necessarily! The subjunctive reflects the speaker's internal state of mind (ignorance or confusion, especially since they are frastornato). The stranger might very well be the doctor in reality, but the speaker just isn't aware of it in that moment.
What exactly does frastornato mean?
It means dazed, bewildered, or confused. It is typically used to describe the dizzy, disoriented feeling you get after a physical shock, a loud noise, or waking up suddenly.
Could I use the infinitive here, like di essere, instead of che... sia?
No, because the subjects of the two clauses are different. The subject of the main clause is 'I' (non so), while the subject of the dependent clause is 'this stranger' (questo sconosciuto). You only use di + infinitive when the subject is the same in both clauses (for example: non so di essere il medico meaning 'I don't know that I am the doctor').