Elixir (Sungwon)

Elixir (Sungwon) manga summary: Eunha is heartbroken when she finds out her high school sweetheart, Siyeon, used an elixir to make her fall in love. When the two reunite 10 years later at a business meeting, Siyeon asks for a second chance. But before they can talk things out and rebuild their trust, greater magical forces interfere.