実に|じつにjitsuni[2]nakadaka (mid-high)

1. adverbreally; truly; indeed; very; extremely; terribly
   今日きょうは実じつによい天気てんきだ。↗

   It is truly a nice day today.

• Synonym誠にまことにFormalFormal and stately, used above all in apologies and thanks, as in 「誠に申し訳ございません」; 「実に」 is for exclaiming at how great a thing is.
• SynonymまったくNeutralPoints to completeness — 'entirely', or 'not at all' with a negative — and doubles as an exclamation like 「全く困ったものだ」; 「実に」 exclaims at degree.
• SynonymいかにもNeutralSays something truly looks the part, as in 「いかにも学者らしい」, and serves as the affirmative reply 「いかにも」; 「実に」 simply exclaims at degree.
• Synonym大変たいへんNeutralEveryday spoken 'very', as in 「大変お世話になりました」; it also works as a na-adjective for something awful or serious, a use 「実に」 lacks.
• Synonym非常にひじょうにNeutralObjective, rather written 'extremely'; 「実に」 carries more of the speaker's emotional exclamation.
• Synonym極めてきわめてWrittenWritten style, as in 「極めて重要だ」; cooler and more formal than 「実に」, which adds a note of feeling.
• SynonymたいそうNeutralOld-fashioned 'very', as in 「大層喜ぶ」, little used today; as a na-adjective it suggests exaggeration or making too much of things.
• Synonym本当にほんとうにNeutralThe default in speech, as in 「本当に嬉しい」; 「実に」 leans written and carries a sigh of feeling.
• Synonym至っていたってNeutralPlain 'extremely' for all sorts of states, as in 「至って元気だ」「至って簡単」; 「実に」 sounds more exclamatory.
• SynonymとてもNeutralThe most common spoken intensifier, as in 「とてもきれい」; 「実に」 leans written and exclamatory.
• Synonym至極しごくWrittenWritten 'extremely', as in 「至極当然」; often appears in the pattern 「～至極」.
• SynonymずいぶんNeutral'Quite' or 'very', as in 「随分寒い」; often adds surprise or a reproach, as in 「随分ひどい」.
• Synonym甚だはなはだWrittenWritten 'very', as in 「甚だ遺憾だ」; used chiefly for negative assessments.
• Synonym大いにおおいにNeutral'Greatly' or 'to the fullest', as in 「大いに楽しむ」; it mainly modifies verbs.
• SynonymだいぶNeutral'Considerably', as in 「だいぶ良くなった」; used mostly for degrees of change.
• Synonym本当ほんとうNeutralA noun or na-adjective for truth and reality; as an adverb it becomes 「本当に」.
• SynonymなかなかNeutral'Quite' or 'rather', as in 「なかなか面白い」; with a negative it means 'not easily', as in 「なかなか来ない」.
• SynonymよほどNeutral'Quite' or 'very', often with conjecture, as in 「よほど疲れたのだろう」; also 'all but' doing something.
• SynonymひどくNeutral'Terribly' or 'badly', as in 「ひどく痛む」; used for negative degrees.
• SynonymよっぽどCasualColloquial emphatic form of 「よほど」, as in 「よっぽど好きなんだね」.
• SynonymまさしくNeutralAsserts that something is exactly so, as in 「まさしく本物だ」; its focus is an accurate judgment rather than how great a thing is, though both can mean 'truly, indeed'.
• Synonym真にしんにWrittenThe same word as 「誠に」; written 「真に」 it stresses being genuinely so, as in 「真に必要なもの」 — more formal than 「実に」.
• Related結構けっこうNeutral'Quite' or 'rather', as in 「結構おいしい」; milder than 「実に」 and often tinged with pleasant surprise.
• RelatedかなりNeutral'Considerably', as in 「かなり難しい」; a weaker degree than 「実に」 and very common in speech.
• Related何よりなによりNeutral'More than anything', as in 「何よりうれしい」; it ranks something top, not merely high in degree.
• Related最ももっともNeutralSuperlative 'most', as in 「最も高い山」; it compares, which 「実に」 never does.
• Related実際にじっさいにNeutralStresses fact — actually seeing or doing something, as in 「実際に見た」 — not degree, so it does not replace 「実に」.
• RelatedすこぶるWrittenWritten and old-fashioned 'extremely', as in 「すこぶる機嫌がいい」; 「実に」 is the more current exclamatory choice.
• RelatedいたくWrittenWritten word for 'deeply', as in 「いたく感動した」; used mostly for feelings.
• RelatedおおきにNeutralIn Kansai dialect 「おおきに」 is a thank-you; as an adverb it means 'greatly' but is rare in modern usage.
• Related世にもよにもNeutralMostly in set phrases like 「世にも不思議な」, 'rare in this world', with a hyperbolic flavor.

Use 「実に」 for an emphatic, exclamatory 'really' or 'very'. In everyday speech pick 「本当に」 or 「とても」. For formal apologies and thanks use 「誠に」. For cool, written prose choose 「極めて」 or 「非常に」. When the degree is milder, 「かなり」 or 「結構」 fits. Some carry a shade of their own: comparison (「最も」), plain fact (「実際に」), negative degree (「酷く」).

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. まことに。本当ほんとうに。
2. 非常ひじょうに。まったく。
3. 長ながい年月としつきや多額たがくの費用ひよう、多大ただいな労力ろうりょくなどにかかって、強調きょうちょうや驚嘆きょうたんを表あらわす。なんと。