Cinderalla's Glass Slipper, The One I've Always Loved

The woman had a crush on the president since she was young, but she didn't dare to approach him because of her fat body. When she grew up, her appearance changed a lot. As his assistant, she accidentally had a relationship with the president, but she was afraid that he would dislike her, so she didn't dare to reveal her identity. Unexpectedly, someone else took her identity and even wanted to kill her...?