Learn Hardcore Russian: Моя жена спокойно объясняет детям, почему важно быть честным. - My wife calmly explains to the children why it is important to be honest.

детям = “to (the) children” (dative plural)
детей is accusative/genitive plural (“children” as a direct object, or “of the children”)
дети is nominative plural (“children” as the subject of a verb)

Here, the children are not doing the action; they are the recipients, so we need dative: детям.

Why is it «спокойно» and not «спокойная» or «спокойная жена»?

Спокойно is an adverb (“calmly”) describing how the wife explains.

спокойно объясняет = “(she) explains calmly”

If you used the adjective спокойная, it would describe the wife, not the manner of explaining:

спокойная жена объясняет детям… = “the calm wife explains to the children…”

Both are grammatically correct but mean different things:

Моя жена спокойно объясняет… — focuses on how she explains (her manner).
Моя спокойная жена объясняет… — focuses on what kind of wife she is (her character).

In the given sentence, we want an adverb (manner of the action), so we use спокойно.

Why is there a comma before «почему»?

In Russian, a comma is used to separate a main clause from a subordinate clause introduced by conjunctions or question words like что, чтобы, когда, потому что, почему, etc.

Main clause: Моя жена спокойно объясняет детям
Subordinate clause: почему важно быть честным

The verb объяснять can be followed by a clause starting with почему:

объяснять, почему… = “to explain why…”

Because почему важно быть честным is a separate clause (even though it depends on объясняет), Russian punctuation requires a comma:

Моя жена спокойно объясняет детям, почему важно быть честным.

What is the difference between «почему» and «зачем» here? Could we say «зачем важно быть честным»?

Both почему and зачем can be translated as “why”, but they are not identical:

почему — asks about the reason / cause
- “Why is it like that? For what reason?”
зачем — asks about the purpose / goal
- “For what purpose? For what aim?”

In this sentence:

почему важно быть честным = “why it is important to be honest” (reasons, justification)
зачем важно быть честным = “for what purpose it is important to be honest” (what being honest is for)

Both are possible in Russian, but:

почему is more neutral when explaining a moral or logical justification.
зачем would sound more like: “What is honesty good for? What do we achieve by being honest?”

Why is «важно» in the neuter form and used without any noun? What is the subject of «важно»?

Russian often uses short-form neuter adjectives as impersonal predicates to express “It is + adjective”:

Важно = “it is important”
Нужно = “it is necessary”
Можно = “it is possible / allowed”

There is no explicit subject like “it.” Russian simply says:

Важно быть честным. — literally “Important to be honest.” (= It is important to be honest.)

So:

важно is neuter singular short form of важный, used in an impersonal construction.
The “it” in English is just a dummy subject and has no direct equivalent in Russian; важно itself carries the meaning “it is important.”

Why do we say «быть честным» and not just «честным» after «важно»?

Here быть честным is an infinitive phrase: “to be honest.”

The pattern is:

важно + infinitive = “it is important to do X”

For example:

Важно говорить правду. — It is important to tell the truth.
Важно слушать других. — It is important to listen to others.
Важно быть честным. — It is important to be honest.

You cannot normally drop быть in the infinitive construction:

✗ Важно честным. — incorrect.
✓ Важно быть честным.

(The only place where быть is often dropped is the present tense of a finite verb, e.g. Он честный instead of Он есть честный, but here we are using an infinitive, not a finite verb.)

Why is «честным» in the instrumental case after «быть»?

With быть in the sense of “to be (someone/something)” or “to be in a certain role / quality,” Russian regularly uses the instrumental case:

быть учителем — to be a teacher
быть врачом — to be a doctor
быть добрым — to be kind
быть честным — to be honest

So честным is:

long-form adjective честный
masculine/neuter instrumental singular

The rule:
When быть links a person to a profession, role, or characteristic, that noun or adjective is usually in the instrumental:

Она хочет быть честной. (fem. instr.)
Они хотят быть честными. (pl. instr.)
Важно быть честным. (here: generic masc./neut. instr.)

Why is «честным» singular masculine/neuter? Shouldn’t it agree with «детям» and be plural, like «честными»?

There are two different possible structures:

General, impersonal statement (no explicit subject)
- Важно быть честным. — “It is important to be honest.” / “One should be honest.”
  Here Russian uses masculine/neuter singular as the default “general person.”
  That is exactly what we have in the sentence:
  …объясняет детям, почему важно быть честным.
  → “She explains why it is important (for people in general) to be honest.”
Statement tied to a specific subject in the dative
- Ему важно быть честным. — It is important for him to be honest.
- Им важно быть честными. — It is important for them to be honest.

If you explicitly want to say “why it is important for the children to be honest,” you can say:

…объясняет детям, почему им важно быть честными.

Here честными becomes plural instrumental to agree with им (them).

In the original sentence, we have the more general moral rule, so Russian naturally uses the generic singular: быть честным.

Why is the verb «объясняет» (imperfective) used, and not «объяснит» (perfective)?

Объяснять (imperfective) vs объяснить (perfective):

объясняет — present tense, ongoing or habitual action
- “is explaining” / “explains”
объяснит — future tense, one completed action
- “will explain (once, successfully)”

In the sentence:

Моя жена спокойно объясняет детям…
suggests:
- it could be something she is doing right now, or
- something she regularly does (habit).

If we say:

Моя жена спокойно объяснит детям, почему важно быть честным.
this means:
- “My wife will calmly explain to the children why it is important to be honest” — a single, expected future event.

Because the English version “My wife calmly explains to the children…” naturally matches a present / habitual meaning, the imperfective объясняет is the right choice.

Can we move «спокойно» to another position in the sentence? Does the word order change the meaning?

Russian word order is flexible, but it affects emphasis and style.

Most natural positions for спокойно here:

Моя жена спокойно объясняет детям, почему важно быть честным. (neutral, standard)
Моя жена объясняет детям спокойно, почему важно быть честным. (slightly emphasizes the calm manner)

Other possibilities:

Спокойно моя жена объясняет детям, почему важно быть честным.
— sounds marked / poetic / contrastive, with strong emphasis on “calmly.”
Моя жена детям спокойно объясняет, почему важно быть честным.
— also possible, with a slight shift in rhythm, but still correct.

The meaning (she explains calmly) remains the same; the differences are mainly in focus and naturalness. The original order is the most neutral.

Why is it «Моя жена» (nominative моя) and not «моей жены» or «моей жене»?

The subject of the sentence is “my wife”, so it must be in the nominative case:

Кто? Что? — моя жена — “my wife” (nominative feminine singular)

Other forms:

моей жены — genitive (“of my wife”)
моей жене — dative (“to my wife”)
мою жену — accusative (“my wife” as a direct object)

Here, my wife is the doer of the action объясняет, so we need nominative:

Моя жена (кто?) объясняет… — “My wife explains…”

Using another case would change the grammatical role and break the sentence.

Could we say «Моя жена объясняет детям, как важно быть честным» instead of «почему важно быть честным»? What is the difference?

Yes, you can say:

Моя жена объясняет детям, как важно быть честным.

The difference:

почему важно быть честным — “why it is important to be honest”
- Focus on reasons: She explains the reasons / justification.
как важно быть честным — literally “how important it is to be honest”
- Focus on degree / emphasis: She explains just how important honesty is.

So:

почему — emphasizes cause / reason.
как важно — emphasizes the level of importance.

Both are natural; they just highlight slightly different aspects of the explanation.