てならない details
fun + can't help feeling X
tanoshi kutenaranai
can't help feeling X; X uncontrollably — a closed set of feeling predicates only
あの日のことが悔やまれてならない。
ano hi no koto ga kuyamarete naranai.
I can't help but regret that day, over and over. formal
早く結果が知りたくてならない。
hayaku kekka ga shiritakute naranai.
I'm dying to know the results already. neutral
- i-adjective stem
- na-adjective
- past
- polite
Examples
can't help feeling X; X uncontrollably — an emotion or sensation so strong the speaker cannot reason it away
あの日のことが悔やまれてならない。
ano hi no koto ga kuyamarete naranai.
I can't help but regret that day, over and over. formal
早く結果が知りたくてならない。
hayaku kekka ga shiritakute naranai.
I'm dying to know the results already. neutral
彼女に会えないのが寂しくてならない。
kanojo ni aenai no ga sabishikute naranai.
Not being able to see her leaves me hopelessly lonely. neutral
最近の物価の上昇が不安でならない。
saikin no bukka no joushou ga fuan de naranai.
The recent rise in prices leaves me endlessly uneasy. formal
Formation
自発の意味を持つ動詞のて形＋ならない（思われて・悔やまれて・気になって）attaches to verb stem (special attachment){I-stem}くてならないattaches to i-adjective stem{NA-stem}でならないattaches to na-adjective
Related patterns
Similar
Near-synonyms, but てならない stays inside a narrow set of mental/emotional predicates (思われる, 心配, 寂しい) and reads written/reserved, while てたまらない takes any strong sensation — physical or emotional (痛い, 眠い, 嬉しい) — and is the everyday spoken default.
Both name a feeling too strong to control, but てならない names the FEELING itself as the predicate (心配でならない — the worry is inescapable), while ないではいられない names the ACTION the feeling forces out (心配で確かめないではいられない — the worry drives an act of checking); one states the state, the other the compelled behavior.
Both intensify an emotion word, but ことに fronts the feeling as commentary on a SEPARATE clause that follows (驚いたことに、彼は来なかった — the surprise stands outside the reported event), while てならない makes the feeling itself the sentence's own main predicate (心配でならない — the worry IS what's being said).
Lookalikes
Both close on ならない, but it contributes none of its dictionary sense ("become") to either — なければならない negates a hypothetical non-occurrence into an obligation (must do), while てならない fixes a feeling predicate into an involuntary intensifier (can't help feeling); skim past the て／なければ split and the two idioms swap.