In 'the open window' by saki which line suggest that mrs sappleton was a sophisticated lady?

The only suggestion in the text that Mrs. Sappleton was a sophisticated later would be the fact that Framton needed a letter of introduction to call on her.

"Hardly a soul. My sister gave me letter of introduction to some people here."

Mrs Sappleton broke into whirl apologies on being late that might suggest she was a sophisticayed lady.