tegami wo okuru mae ni, atesaki wo mou itido kakuninsimasu.

It is read:

てがみ を おくる まえ に、あてさき を もう いちど かくにんします。

Word by word:

• 手紙 = てがみ = letter
• 送る = おくる = to send
• 前に = まえに = before
• 宛先 = あてさき = address / destination / addressee
• もう一度 = もういちど = one more time / again
• 確認します = かくにんします = confirm / check

Because the pattern is:

• Verb dictionary form + 前に = before doing ...

So:

• 送る前に = before sending

This is a very common grammar pattern.

Examples:

• 食べる前に、手を洗います。 = Before eating, I wash my hands.
• 寝る前に、本を読みます。 = Before sleeping, I read a book.

So in your sentence, 手紙を送る前に means before sending the letter.

に marks the time point at which something happens.

So:

• 送る前に、確認します。 = I check before sending.

In many sentences, 前に sounds most natural and standard when expressing before doing something.

You may sometimes see 前 without に, but 前に is the basic form learners should remember first.

Because there are two different actions, and each action has its own direct object.

1. 手紙を送る

   • 手紙 is the thing being sent
   • so it takes を

2. 宛先を確認します

   • 宛先 is the thing being checked
   • so it also takes を

So the sentence is built from two parts:

• 手紙を送る前に = before sending the letter
• 宛先をもう一度確認します = I check the address one more time

宛先 means the destination or addressed recipient, and in this sentence it usually means the mailing address.

For a letter, 宛先 is the information showing where or to whom the letter is being sent.

It can be translated as:

• address
• destination
• addressee

In this context, address is the most natural translation.

もう一度 means one more time or again, with a clear sense of repeating the action once more.

So:

• 宛先をもう一度確認します = I check the address one more time.

また can also mean again, but it is broader and does not specifically emphasize one more time in the same way.

Compare:

• もう一度確認します = I’ll check it one more time.
• また確認します = I’ll check it again.

In your sentence, もう一度 sounds very natural because it suggests a careful re-check.

Japanese non-past forms can express:

• habitual actions
• present/future actions
• general statements

So 確認します can mean:

• I check
• I will check
• I check as a habit

The exact meaning depends on context.

Here, it most naturally means something like:

• I check the address again before sending the letter.

It sounds polite and neutral because of 〜ます.

確認する means more than just look at. It means:

• confirm
• verify
• check carefully to make sure something is correct

That matches the situation well: before sending a letter, you do not just look at the address, you verify it.

Compare:

• 宛先を見ます = I look at the address.
• 宛先を確認します = I check/confirm the address.

So 確認します is more precise and more natural here.

Yes. 手紙を送る前に is a subordinate time clause.

It sets up when the main action happens:

• Before sending the letter, ...

Then the main clause is:

• 宛先をもう一度確認します。
• ... I check the address one more time.

So the full structure is:

• [Before sending the letter] [I check the address again].

This is very common in Japanese: a time clause comes first, then the main action.

No, 送るの前に is not natural here.

With 前に, you normally use:

• dictionary form verb + 前に
• noun + の + 前に

So:

• 送る前に = correct
• 食べる前に = correct
• 会議の前に = correct
• 昼ご飯の前に = correct

But:

• 送るの前に = not correct in normal Japanese

So remember:

• verb → plain form + 前に
• noun → noun + の + 前に

No, it is not strictly necessary, but it is very common and helpful.

The comma shows a pause after the opening time phrase:

• 手紙を送る前に、宛先をもう一度確認します。

Without the comma, the sentence is still understandable:

• 手紙を送る前に宛先をもう一度確認します。

The comma just makes it easier to read.

Yes, to some extent. Japanese word order is more flexible than English, as long as the particles make the roles clear.

For example, this is also possible:

• 宛先をもう一度、手紙を送る前に確認します。

But the original order is the most natural and easy to follow:

• 手紙を送る前に、宛先をもう一度確認します。

Japanese often puts the time condition first, then the main action.

Yes, it sounds very natural. It gives the feeling of a careful, sensible action:

• before sending a letter,
• you check the address again to avoid mistakes.

It also sounds slightly formal or neat because of words like:

• 宛先
• 確認します

So this is the kind of sentence you might see in instructions, polite conversation, or standard written Japanese.