Who is Madame Sofronie?

Despite scrimping and saving for many long months, Della has only been able to save a dollar and eighty-seven cents to purchase a Christmas gift for her beloved husband, Jim. She cries because she so longs to buy him something worthy of him, but she does not have any other way to come up with the money or even anything of value that she can sell—nothing except her "beautiful hair," her most prized possession. When she lets it down, it falls "about her, rippling and shining like a cascade of brown waters."
It occurs to her that she might sell her hair in order to acquire the money she needs to buy Jim a beautiful gift. Madame Sofronie is the owner of the shop that deals in "Hair Goods of All Kinds." She is described as "hardly looking the 'Sofronie,'" perhaps because it is such a beautiful-sounding name and Madame herself is "large, too white, [and] chilly." She is standoffish and disinterested, quite a contrast to the warm and cozy feeling Jim and Della have created in their little home. Madame Sofronie could be interpreted as a symbol of the cold, uncaring world outside the Dillinghams' relationship, drawing even more attention to their priorities and values as the "wisest."
Madame Sofronie is driven by money; Della and Jim are motivated by love.

Madame Sofronie is characterized as a cold, tough, unsympathetic woman who is only pretending to be a foreign-born artiste for business purposes; she actually appears to be from Brooklyn. She puts on airs with her customers but not with a girl like Della, who is a seller and not a buyer. Madame Sofronie gives herself away when she says, “Take yer hat off and let's have a sight at the looks of it.” This woman must realize that Della is feeling distressed and even frightened, but she deals with many such desperate young girls who need money and have nothing else to sell.
O. Henry uses the episode with Mme. Sofronie to emphasize the ordeal Della has to go through in selling her beautiful long hair. It is a sufficiently painful experience to part with her hair without having to deal with a woman like the hard-boiled businesswoman who calls herself Madame Sofronie. O. Henry is not interested in characterizing hair buyers in general; he only invents this unpleasant character in order to highlight the sacrifice that Della is making. Della is like a shorn lamb.