〜にほかならないIs nothing but ~ / Is exactly ~ (strong assertion)
彼が失敗したのは、準備不足にほかならない。
His failure is nothing but lack of preparation.
💡Very strong assertion: X = nothing but Y. Formal/written Japanese.
〜なしに(は)Without ~ (cannot do something)
この条件なしに、契約を締結することができません。
Without these conditions, we cannot conclude the contract.
💡〜なしに = without ~. Stronger than 〜がなければ. Often written form.
〜なくして(は)Without ~ (essential condition, would be impossible)
彼女の努力なくして、このプロジェクトの成功はあり得なかった。
Without her efforts, the success of this project would not have been possible.
💡Even stronger than なしに; emphasizes an essential, indispensable condition.
〜と言っても過言ではないIt is no exaggeration to say that ~
情報リテラシーは不可欠と言っても過言ではない。
It is no exaggeration to say that information literacy is indispensable.
💡過言（かごん）= exaggeration. Very common in formal essays and speeches.
〜ならでは(の)Uniquely possible for ~ / Only achievable with ~
これほどの偉業は、彼女ならではできないことだ。
Such a great achievement is something only she can do.
💡Highlights a unique quality or ability that only that person/thing possesses.
〜を糧とするTo use ~ as nourishment / as a stepping stone
彼は失敗を糧として、さらに奮起した。
He used his failure as a stepping stone and motivated himself further.
💡糧（かて）= food/nourishment (metaphorical). Used to describe turning adversity into strength.
〜に反してContrary to ~ / Against ~ (expectations/rules)
政府の政策は国民のニーズに反していると言わざるを得ない。
It must be said that government policy is contrary to the needs of the people.
💡反する = to go against. Often used in critique. 〜に反して = contrary to [noun].
〜べきだShould ~ / Ought to ~ (moral obligation)
どんな困難に直面しようとも、諦めないべきだ。
No matter what difficulties one faces, one should not give up.
💡Expresses strong moral/social obligation. 〜べきではない = should not ~.
〜ないことにはUnless ~ (strong conditional; without X, Y is impossible)
問題の本質を見極めないことには、表面的な対処に終わってしまう。
Unless we identify the essence of the problem, we end up with only superficial measures.
💡Stronger than 〜なければ. Emphasizes that X is an absolute prerequisite for Y.
言わざるを得ないCannot help but say ~ / Must say ~
この結果は失望せざるを得ない。
One cannot help but be disappointed by this result.
💡ざるを得ない = cannot avoid doing ~. Classical negative form + を得ない. Very formal.