Final answer:
The mother wants to add a lace collar to the dress to enhance its beauty and indicate the social status or personal transition of the character wearing it, as clothing is often used in literature and art to symbolize such themes.
Step-by-step explanation:
The mother likely wants to put a lace collar on the dress to enhance its elegance and to signify the social status or coming of age of the wearer, which is often reflected through attire in literature. In the various excerpts provided, clothing is depicted as a key element in portraying a character's status and life changes. From Mrs. Boldin adding lace to surprise the delivery-boy to the symbolic representation of family dynamics in the artwork 'Asoebi - Lace, Sweat, and Tears,' where attire plays a role in highlighting relationships, the addition of a lace collar can be seen as an effort to beautify the dress and make a statement about the wearer’s refinement or transition in society.