Zhai Hua could not possibly lie to Wei De that her father was happy about their relationship.
When Wei De's incident had been escalated to Zhai Yaohui, Zhai Hua got a foreboding that it was the end of her relationship with Wei De. She thought that her father would never agree to their relationship. He might even get Old Master Zhai to come to Ping Cheng, and the two of them would heartily criticize her and force her to leave Wei De and never to see Wei De again.
Zhai Hua had even come up with ways to defend her love for Wei De and to withstand the pressure that her family gave her.
Therefore, Zhai Hua was full of gratitude that Zhai Yaohui only ordered Zhai Sheng to expel Wei De from the army. He did not force Zhai Hua to leave Wei De. Though he did not agree to their relationship, he did not object to them as well.
Therefore, Zhai Hua could not lie to Wei De that Zhai Yaohui agreed to their relationship.