。
She was ashamed of her child's behavior.
Literal
She [topic-は] child [genitive-の] behavior [object-を] was-ashamed-of.
恥じる ('to be ashamed of, feel shame about') is a transitive verb taking を, unlike English 'ashamed' which needs the preposition 'of.' The English speaker has to remember to drop the preposition: 振る舞いを恥じる, not 振る舞いに恥じる. 振る舞い ('behavior, conduct') is built from 振る舞う ('to behave, conduct oneself'), where the literal 'swing-dance' kanji combination paints behavior as something performed in front of others — fitting for a culture that pays close attention to public conduct.