The ribbon seller

An original fiction passage set in the nineteenth century.

Miss Vale had arranged the ribbons in a fan of colour across the counter. The customer asked for the palest blue, rejected it, then requested precisely the same shade from another drawer. Miss Vale smiled and opened the drawer. Her smile was a door she kept firmly shut. Behind it, she considered the unpaid rent and the fact that the customer had already occupied half the morning without purchasing anything.

Identify the phrase which suggests that Miss Vale conceals her true feelings.