Mariana Mariana
The story runs in the 1940s Mexico City. A schoolboy (Carlos) falls in love with his best friend's mother (Mariana). Carlos is impressed because this family is not like the ordinary mexican families of the time, because they have many expensive American things, although they are not rich. The drama begins when Carlos gets out of school to go to declare his love to Mariana, and is discovered by his teachers.
Starring Pedro Armendáriz Jr., Elizabeth Aguilar, Saby Kamalich, Aarón Hernán, Luis Mario Quiroz, Juan Carlos Andrews, Gerardo Quiroz, José Luis Cruz, Adolfo Olmos, Jun Kawabe
Watch "Mariana Mariana" on Mubi released in 1987. It's a drama and romance movie, and has a rating of 7 out of 10 from Imdb which is usually fine for this kind of movie.