She and Allan by H. Rider Haggard

Thus I spoke whose nerves were on edge after all that I had seen or, as even then I suspected, seemed to see. For how could I believe that these visions of mine had any higher origin than Ayesha's rather malicious imagination? Already I had formed my theory.

It was that she must be a hypnotist of power, who, after she had put a spell upon her subject, could project into his mind such fancies as she chose together with a selection of her own theories. Only two points remained obscure. The first was-how did she get the necessary information about the private affairs of a humble individual like myself, for these were not known even to Zikali with whom she seemed to be in some kind of correspondence, or to Hans, at any rate in such completeness?