Я хочу пожелать тебе спокойной ночи.

Because the sentence literally means I want to wish you a good night, not simply I wish you a good night.

• хочу = I want
• пожелать = to wish (perfective)

So:

• Я хочу пожелать тебе спокойной ночи = I want to wish you a peaceful/good night

If you removed хочу, the meaning would change:

• Я желаю тебе спокойной ночи = I wish you a good night
• Я хочу пожелать тебе спокойной ночи = I want to wish you a good night

Russian often uses this structure when the speaker is introducing a wish in a slightly softer or more formal way.

This is an aspect difference.

• желать = imperfective
• пожелать = perfective

In this context:

• желать focuses more on the process or general act of wishing
• пожелать focuses on a single completed act: to offer a wish

So пожелать is very natural when you are making one specific wish to someone.

Compare:

• Я желаю тебе удачи = I wish you luck
• Я хочу пожелать тебе удачи = I want to wish you luck

Both are correct, but пожелать often sounds like one complete, intentional wish.

Тебе is the dative case of ты.

It means to you.

The verb желать / пожелать normally takes:

• the person receiving the wish in the dative
• the thing being wished usually in the genitive

So in this sentence:

• тебе = to you
• спокойной ночи = a peaceful night / good night

This is a very common Russian pattern:

• желаю тебе счастья = I wish you happiness
• желаю тебе здоровья = I wish you health
• желаю тебе удачи = I wish you luck

Because тебе and тебя are different cases with different jobs.

• тебе = dative = to you
• тебя = accusative/genitive = you

After пожелать, Russian uses the dative for the person who receives the wish.

So:

• пожелать тебе = to wish to you

Not:

• пожелать тебя — this is incorrect here

English does not show this difference clearly because English just uses you for many functions, but Russian does.

Because after желать / пожелать, the thing being wished is usually put in the genitive case.

The basic form is:

• спокойная ночь = a peaceful night

But in this sentence it changes to the genitive:

• спокойной ночи

This is the same pattern as:

• желаю удачи = I wish you luck
• желаю счастья = I wish you happiness
• желаю здоровья = I wish you health

So спокойной ночи is not the dictionary form of the noun phrase; it is the form required by the construction.

It is genitive singular.

Breakdown:

• ночь = nominative singular, night
• ночи = genitive singular

And the adjective agrees with the noun:

• спокойная → nominative singular feminine
• спокойной → genitive singular feminine

So:

• спокойная ночь = basic form
• спокойной ночи = genitive form used after пожелать

Yes, very often.

By itself, Спокойной ночи! is the normal Russian equivalent of Good night!

So the full sentence:

• Я хочу пожелать тебе спокойной ночи

contains the same expression, just inside a larger sentence.

You can think of it like this:

• Спокойной ночи! = Good night!
• Желаю тебе спокойной ночи. = I wish you a good night.
• Я хочу пожелать тебе спокойной ночи. = I want to wish you a good night.

Yes, but it is a bit more expanded than the simple everyday Спокойной ночи!

It sounds natural in contexts like:

• a message
• a speech
• a letter
• a warm or slightly formal statement

For everyday conversation, Russians more often just say:

• Спокойной ночи!

The full sentence sounds more deliberate, like you are explicitly expressing your wish.

Yes, often it can.

Russian frequently drops personal pronouns when they are clear from the verb form.

So these are both possible:

• Я хочу пожелать тебе спокойной ночи
• Хочу пожелать тебе спокойной ночи

The second one is also natural, because хочу already shows I want.

Including Я can add a bit of emphasis or clarity.

Yes, Russian word order is flexible.

This version is the most neutral and straightforward:

• Я хочу пожелать тебе спокойной ночи

But other orders are possible for emphasis, for example:

• Тебе хочу пожелать спокойной ночи — emphasizes to you
• Спокойной ночи хочу пожелать тебе — emphasizes good night

Even though word order can change, the case endings still show the grammatical roles:

• тебе is still the recipient
• спокойной ночи is still the thing being wished

So Russian relies less on word order than English does.

Тебе is the informal singular form: to you when speaking to one person informally.

Use вам if:

• you are speaking formally to one person
• you are speaking to more than one person

Compare:

• Я хочу пожелать тебе спокойной ночи = I want to wish you good night (informal, one person)
• Я хочу пожелать вам спокойной ночи = I want to wish you good night (formal or plural)

This is an important distinction in Russian.