What are the subtle ways in which the lady manages to deceive Horace Danby into thinking she is the lady of the house? Why doesn't Horace suspect that something is wrong?

The description of the lady makes her seem fit as the lady of the house. She was nowhere to be seen unless Horace sneezed which must have caused noise in the silent house. She cleverly manipulated Horace by saying that she had just arrived and wasn’t expecting a thief. She threatened him that she would call the police if he tried to escape. Such a call, made Horace nervous and his fear of going to the prison didn’t allow him to suspect her in any case.