Come In lady Suying!
Ashen shook his head before replying with a smile: "No lady Suying, I think you heard wrong because wang and fang are similar to pronounce"
"Ah, you're right, otherwise, the heavens would've turned angry and lightning would've struck you!" Lady Suying said with a smile.
Ashen used his correct name because if you take an oath with a false name, the heavens would punish you and strike you with lightning. Oath wasn't a joke.
Ashen also took the oath with utmost caution, specifying that he would only protect them from the Bi family and nobody else. Also, he mentioned a time limit that was till they remained under his care.
Next, he also mentioned protecting them to the best of his capabilities, meaning if he didn't hear about their trouble, he wouldn't be punished for not protecting them. Only if he could do something to protect them, then only was he obliged to do it.