Who is Etsy Adelstein from The Smoothest Way Is Full of Stones and what is their importance?

Esty Adelstein is Rebecca's older cousin. She is described as a mischievous girl, who talks back to her mother and does naughty things such as throwing bits of paper at old ladies in the synagogue. After her mother took her to Israel, however, Esther repented her former ways and became pious. She spends a lot of her time praying and studying the Torah and telling her cousin Rebecca that she and her mother should be more observant of Jewish religious rituals and customs. But ironically, it is Esty, in her willingness to read the book Essence of Persimmon: Eastern Sexual Secrets for Western Lives and in her boldness in making a nocturnal appointment with Dovid and daring to kiss him, who shows herself to be more reckless, less concerned with following the precepts of her religion than her supposedly more secular cousin Rebecca. Although she may not realize it, Esty is somewhat hypocritical in her attitudes, doing exactly what she wants while presenting a pious exterior.