。
She doesn't like going to school.
Literal
She [topic-は] school [direction-へ] go [object-を] dislike-shows.
嫌がる ('to show signs of disliking / be reluctant') is the third-person observable form of the adjective 嫌い ('disliked'). Japanese makes a careful distinction here: 嫌い describes an inner state (the speaker's own feelings, since you can directly know them), while 嫌がる describes outwardly observable reluctance (used for others, since you can only see their behavior). The same ~がる suffix attaches to other emotions: 痛がる ('show signs of pain'), 怖がる ('show fear'), 寂しがる ('act lonely'). This is part of a broader Japanese pattern of treating other people's inner states as unknowable, and only commenting on visible behavior. The のを nominalizes 学校へ行く so it can take を as the object of 嫌がる.