In fact, Le Wan wasn't lying. The Le family had indeed taught their children some basic martial arts lessons. However, the original body was too delicate when she was young, and didn't take the lessons seriously at all. She had basically just muddled through the lessons, so she didn't have any actual combat ability at all.
The Kungfu that Le Wan was currently using was something that she had learned in her previous life before her rebirth. At that time, she heard in the interest class, that the young teacher who practiced martial arts with her would pay more than the other classes.
So, she took advantage of the fact that she had studied for two years when she was young and went to attend an interview. In the end, she successfully stayed in the martial arts class by not being afraid of hardship, fatigue, or pain.