I obviously misread "Ivan" for "Zaroff" in answering the above post. A proper answer would be that "No," Ivan was in no way disarming during any part of Rainsford's visit. The gigantic nature of the man and his wordless greeting--with a revolver pointed at Rainsford's heart--stunned Rainsford who, nevertheless, tried to disarm Ivan with a casual smile.
First, the definition of disarming is to diminish or reduce the feeling of suspicion or hostility by winning the favor or confidence of another. So, to answer your question, yes, Zaroff's behavior toward Rainsford was disarming--at first. When Rainsford first reached Zaroff's mansion, he was greeted by Ivan, armed with a pointed pistol. But Zaroff soon made Rainsford feel at ease.
In a cultivated voice marked by a slight accent that gave it added precision and deliberateness, he said, "It is a very great pleasure and honor to welcome Mr. Sanger Rainsford, the celebrated hunter, to my home."
Automatically Rainsford shook the man's hand.
Zaroff's cultured mannerisms and the beautiful luxuries within his home soon made Rainsford feel comfortable. Zaroff assured him it was "a most-restful spot." The good food and drink calmed Rainsford, who
... was finding the general a most thoughtful and affable host, a true cosmopolite.
But the general's habit of constantly staring at him, studying him, began to make Rainsford more uncomfortable. Zaroff's talk of his hunting past enthralled Rainsford, escpecially when the Cossack spoke of having invented "a new animal to hunt."
Rainsford leaned across the table, absorbed in what his host was saying.
But when Rainsford finally understood the true nature of Zaroff's new type of prey, Rainsford's shock became evident, and he soon excused himself for his bedroom to reconsider the murderous man who was his host.
Thank you hat really did help alot.