Answer:
The narrator hears her grandmother tell the story of receiving her first love letter, and the reader finds out that Abuela still loves Alejandro.
Step-by-step explanation:
In "Modern Love Letter" we can see that the fact of writing letters and sternalizing their own feelings is a great act of courage and resistance, besides being revealing and causing great suspense and surprise to the reader, mainly due to the first person narration that has the ability to convey the narrator's deepest feelings to the reader.
This happens when the narrator finds out that the love letters she had access to were for Abuela, someone so close to her and that she has such a strong impact on her life.