If she were not glad, she would not be in her senses, in other words she would not be sane, and should be treated as a lunatic, for her own good.

Would you let a lunatic do as he liked, if he tried to jump out of the window?
The mere thought is absurd." "Quite," said Zorzi.
Sad as he was, he could almost have laughed at the old man's inconsequent speeches.
"I am glad that you so heartily agree with me," answered Beroviero in perfect sincerity.

"I do not mean to say that I would ask your opinion about my daughter's marriage.

You would not expect that.

But I know that I can trust you, for we have worked together a long time, and I am used to hearing what you have to say." "You have always been very good to me," replied Zorzi gratefully.
"You have always been faithful to me," said the old man, laying his hand gently on Zorzi's shoulder.