As he ran to fish it out the girl on lawyer Royall's doorstep noticed
that he was a stranger, that he wore city clothes, and that he was
laughing with all his teeth, as the young and careless laugh at such
Her heart contracted a little, and the shrinking that sometimes came
over her when she saw people with holiday faces made her draw back into
the house and pretend to look for the key that she knew she had already
put into her pocket.
What exact emotion are we talking about here? Surely not fear? Either that she was emotionally excited at the sight of "him", or that she was to some degree frightened by him - the context is not enough to be sure. Whichever it is, adrenalin pumping into the system produces this sense of the heart contracting.
When a person falls in love with someone, the sight of that person produces this sensation.
And what about a lightness of heart?
In the street she stood still, dazed by this last adventure. But the
brooch lay in her bosom like a talisman, and she felt a secret lightness
of heart. It gave her strength, after a moment, to walk on slowly in the
direction of the post office, and go in through the swinging doors.
She is happy and relaxed and her spirits are high.
Or a softness of heart?
... and she felt a softness at her heart which no act of his had
ever produced since he had brought her the Crimson Rambler because she
had given up boarding-school to stay with him.
She is pleased by what he has done and is feeling contented and gentle.