To Li Jun what Li Wei was doing just seemed like a act of stupidity. The situation Li Jun was in Jun knew that Wei had changed a lot in many ways but he couldn't tell what has changed.But he didn't care how Li Wei changed since to Jun, Wei was stupid as she always was and will be dumb forever.
Previous Wei wouldn't even dare to look at Jun's eyes as he was always scare of Jun but current Wei not only looked into his eyes but also dare to smile a happy smile which seemed like an act to provoke him. Jun thought it was just a little show of his bother Wei to show him that he was brave now but inside he was mick and timid as always.
Just then Jun remember his sister trembling and explaining all that happened in school. Fan said that Wei turned in to reincarnation of devil king and Wei's cold aura could freeze any one but it seems like it was all illusion of Fan's to Jun because of the cheerful smile which could even melt frozen ice. Every thing Fan said to Jun about Wei was being wronged.
The arrogant nature, cold eyes, creepy smile, urge to kill someone, look of revive Demon king and other terrifying words describing Wei by Fan's mouth were opposite of how Wei was appearing at Jun's eyes.
Jun saw an idiotic, angelic and cheerful person who doesn't know how world works and who would trust anyone infront of him. Wei's act was not some amateur actor performance but rather a professional one so even Li Jun couldn't see through it.