～にほかならない— Nothing Other Than

• 彼の成功は努力の結果にほかならない。

  Kare no seikou wa doryoku no kekka ni hokanaranai.

  His success is nothing other than the result of hard work.

  結果 + にほかならない emphatically identifies effort as the sole cause of success.

• この事故の原因は不注意にほかならない。

  Kono jiko no gen'in wa fuchuui ni hokanaranai.

  The cause of this accident is nothing but carelessness.

  不注意 + にほかならない insists that carelessness is the one and only cause.

• 言葉は文化の反映にほかならない。

  Kotoba wa bunka no han'ei ni hokanaranai.

  Language is nothing but a reflection of culture.

  反映 + にほかならない definitively equates language with a cultural reflection.

• ・Register: formal / written; frequent in essays and argument.
• ・Carries strong conviction — 'this is the definitive truth'.
• ・Common mistake: attaches to nouns; not used for casual everyday claims.

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones ～にほかならない is tested against.

• ～こそ — This Is The One
• ～ことか — How Very ...!
• ～ことに(は) — To My Surprise
• さえ — Even That Much
• ～てしょうがない／～てしかたがない — Unbearably So
• ～てたまらない — More Than One Can Bear
• ～てならない — Can't Help Feeling
• ～てばかりいる — Doing Nothing But