Mrs. Herd didn't really understand what Ethan Herd meant, but she thought: My son speaks so well, my son is so good, and my son is so right.
Mrs. Herd is actually a very persistent person. Once she approves of someone, she will feel they are better and better, even their shortcomings are seen as good in her eyes, and so good that others can't say a bad word about them.
In Mrs. Herd's eyes, Ethan Herd is really nothing more than being handsome and wealthy.
However…Mrs. Herd can say it herself, but others are not allowed to say it. Whoever says it, she gets angry with them.
The same goes for Scarlett Glenn. Whether Scarlett Glenn is good or bad, she is the young lady Mrs. Herd likes. She is the daughter-in-law Mrs. Herd approves of. Mrs. Herd doesn't care about others. She just likes this one. She doesn't like any other young lady no matter how good they are. She only likes Scarlett Glenn.
So, no one else can say anything bad about her.