She was exquisitely anxious that I should know it too.
Floodgates of relief were expressed when she saw that I knew it.

Not that I, personally, counted a scrap.

What she craved was a decent human soul's justification of her doings.

She craved recognition of her action in casting away base metal forever and taking the pure gold to her heart.
"Tell me that I am doing the right thing, dear," she said, "and to-morrow I'll be the happiest woman in the world." And I told her, in the most fervent manner in my power.
"You quite understand ?" she said, standing up, looking very young and princess-like, her white throat gleaming between her furs and up-turned chin.
"You will find, my dear," said I, "that the significance of your Dead March of a Marionette will increase every day of your married life." She stiffened in a sudden stroke of passion, looking, for the instant, electrically beautiful.
"I wish," she cried, "someone had written the Dead March of a Devil." She bent down, kissed me, and went out in a whirr of furs and draperies.
Of course, all I could do was to scratch my thin iron-grey hair and light a cigar and meditate in front of the fire.

I knew all about it--or at any rate I thought I did, which, as far as my meditation in front of the fire is concerned, comes to the same thing.
Betty had cast out the base metal of her love for Leonard Boyce in order to accept the pure gold of the love of Willie Connor.