Delfina Edwards Bello comes from the prestigious Edwards family in Chili. Her brother Joaquìn Edwards Bello was a famous writer. She married Bernard Boutet de Monvel in 1921, after they met through the artist's brother, Roger, in Biarrtiz in 1917. The same year, Vogue chose to write an article on her taste for grand French designers. This painting, one of the artist's most beautiful and stunning portraits, was executed in 1936. Delfina is sitting on a chair which is included in the sale, lot 77.
(http://www.sothebys.com/en/auctions/ecatalogue/2016/collection-boutet-de-monvel-pf1639/lot.32.html)