"her face gave absolutely no sign of recognition." Do you think the woman did not recognise the character or was she just pretending?

Mrs Dorling pretended not to recognise the narrator. She did so as she feared she would have to return all of the things belonging to the narrator's mother. Mrs Dorling had brought them to her house during wartime on the pretext of keeping them safely. But, she had used them and had no intention of returning them.