Final answer:
Charlotte admires Jane's ability to conceal her emotions while falling in love with Mr. Bingley.
Step-by-step explanation:
Charlotte admires Jane's ability to conceal her emotions when she is falling in love with Mr. Bingley. This can be seen when Charlotte says, "If there were anything that a good woman could do to win a man and still preserve her self-respect, it was something which escaped the natural subtlety of a woman determined to allure." Charlotte recognizes that Jane is able to maintain her composure and not reveal her feelings for Mr. Bingley, which Charlotte admires.