とは限（かぎ）らない is regularly used to convey the meaning of ‘(A) is not necessarily so’, or ‘there is no guarantee that (A)’. This expression utilizes the 格助詞（かくじょし） (case marking particle) と in its use for highlighting 結果（けっか） ‘results’, the 副助詞（ふくじょし） (adverbial particle) は, and the negated form of the う - Verb 限（かぎ）る ‘to limit’.
This structure may be used with verbs, い-Adjectives, な-Adjectives, or nouns. However, だ will be required after な-Adjectives and nouns.

• 日本（にほん）に2年（ねん）間（かん）住（す）んでいるからといって、日本語（にほんご）を話（はな）せるとは限（かぎ）らない。
  It is not limited to a person being able to speak Japanese just because they have lived in Japan for 2 years.
• 日（ひ）が出（で）てても暖（あたた）かいとは限（かぎ）らない。
  Just because the sun is out, doesn't necessarily mean that it is warm.
• 田舎（いなか）でも静（しず）かだとは限（かぎ）らない。
  A place being rural doesn't necessarily mean that it is quiet.
• 社長（しゃちょう）だからといって乗（の）っている車（くるま）が高級車（こうきゅうしゃ）だとは限（かぎ）らない。
  It is not limited to him driving a luxury car, just because he is the CEO.

限（かぎ）らない literally means ‘to not be bound’, or ‘to not be limited’. Therefore, despite と highlighting a result, that result is then being clarified as ‘not the only possibility’.