MC is a noblewoman. It's part of the culture to sponsor an orphan so they will have better life. She picked up a girl with magical talent but the girl turns out to be a sociopath who leeches off her and ultimately throws her away. MC is second chance'd and sponsors a boy with magical talent instead, who was framed for bullying the girl but is actually the victim. I think I stopped reading because it wasn't translated very far. I remember last reading that the mage boy makes a bridge for her mother's trade caravan to cross.
Is it a kr novel? Edit: Not sure but check this one out. The beginning is similar at least... https://www.novelupdates.com/series/dont-trust-the-heroine/