Моя дружина приїде опівдні.

Because дружина is a feminine singular noun, and мій changes to agree with the noun.

So:

• мій = masculine
• моя = feminine
• моє = neuter
• мої = plural

Since дружина is feminine, you need моя.

Compare:

• мій чоловік = my husband
• моя дружина = my wife
• моє місто = my city
• мої друзі = my friends

Yes. In modern everyday Ukrainian, дружина means wife.

A few useful contrasts:

• дружина = wife
• подруга = female friend
• жінка = woman, and sometimes wife depending on context

So дружина is the clearest and most specific word for wife.

Приїде means will arrive or will come, and the future meaning is already built into the verb.

It is the 3rd person singular future form of приїхати.

So Ukrainian does not need a separate word like English will here. In this sentence, приїде by itself already means:

• he will arrive
• she will arrive
• it will arrive

depending on context.

This is very normal in Ukrainian, especially with perfective verbs like приїхати.

This is an important difference.

• прийде comes from прийти and usually means will come on foot
• приїде comes from приїхати and usually means will arrive by transport or will ride/drive in

So Моя дружина приїде опівдні suggests that your wife is arriving by car, bus, train, plane, taxi, and so on.

If she were walking, you would normally say Моя дружина прийде опівдні.

Because in Ukrainian, present-tense and simple future verb forms do not show gender.

So приїде can refer to:

• he will arrive
• she will arrive
• it will arrive

The subject tells you who it is.

Gender shows up clearly in the past tense, for example:

• Він приїхав = he arrived
• Вона приїхала = she arrived

So in your sentence, the feminine subject is shown by моя дружина, not by the verb form приїде.

Опівдні means at noon or at midday.

It is a fixed time expression, written as one word. English uses a preposition in at noon, but Ukrainian often does not need one in expressions like this.

So:

• опівдні = at noon

You can think of it as a ready-made adverb of time.

Yes. Ukrainian word order is flexible, and changing it usually changes the emphasis, not the basic meaning.

Your sentence:

• Моя дружина приїде опівдні.

is a neutral, natural way to say it.

Other possible orders include:

• Опівдні приїде моя дружина.
  This puts more focus on at noon.

• Моя дружина опівдні приїде.
  Also possible, with slightly stronger emphasis on the timing or on the arrival.

So the original sentence is a good default order, but it is not the only possible one.

Not if you mean one single arrival.

Приїде is the best choice for a one-time completed future event: she will arrive.

The forms приїжджатиме or буде приїжджати are imperfective and usually suggest something like:

• repeated action
• habitual action
• ongoing process

So they fit meanings like:

• She will be arriving at noon every day this week
• She will keep coming at noon

For one simple future arrival, приїде is correct.

A rough pronunciation guide:

• моя ≈ mo-YA
• дружина ≈ droo-ZHY-na
• приїде ≈ pry-YI-de
• опівдні ≈ o-piv-dni

A few important points:

• In приїде, the ї is pronounced separately, like yi.
• So приїде has three syllables: при-ї-де.
• Ukrainian и is not the same as English ee. It is shorter and more central.
• In дні, the д is soft because of the following і.

If you get one thing right first, make it this: do not swallow the ї in приїде.