She doesn't like sushi.

Literal

She [topic-は] sushi [subject-が] liked is-not.

好きではありません is the polite negative of 好き (liked/fond of). Japanese expresses 'like' with the adjective 好き rather than a verb — the thing liked takes が, not を. 寿司 here uses kanji rather than the more casual katakana スシ. The polite negative form makes this a neutral, conversational statement.