Here's the storyline that I remember, fl is inlove with her neighbour, Which is the ml. They meet when they were still children amazed at the ml and ml's family because they are gorgeous yet the fl is normal girl with freckles. She met his sickly sister and observed that the guy he likes looks differently at his sister (blood-related)
The story goes like this, she was known in the village for being "(name of the child her mage sister's child)'s mom" also that child calls her mother even tho she is not her mother she doesn't really mind being called like that but the child insists in which the fl let her call her that (which is a bit Sus because the child looks exactly like fl not the fl's sister), then many years later, ml who slept with the fl in their academy days found her and assumed to be the father of that child and the typical wanting to take responsibility yada yada in which the fl countered that it was her sister's daughter not hers yada yada