kaikei no mae ni, kingaku wo mou itido kakuninsimasita.

の links the noun 会計 with 前.

• 会計 = checkout, payment, accounting, the bill-paying process
• 前 = before, front

When 前 means before in time, it often follows a noun with の:

• 食事の前に = before the meal
• 授業の前に = before class
• 会計の前に = before paying / before checkout

So 会計の前に means before the checkout/payment.

Here, 会計 most naturally means paying the bill, checkout, or settling the payment.

This word can have different meanings depending on context:

• accounting
• the bill/check
• payment / checkout

In this sentence, because it is followed by の前に and the speaker checked the amount, the meaning is clearly something like before paying or before checking out.

The に marks the time point before which the action happens.

So:

• 会計の前に = before checkout
• 寝る前に = before sleeping
• 行く前に = before going

In this sentence, 確認しました happened at the time before checkout, so に is used.

を marks the direct object of the verb.

The verb is 確認しました = checked / confirmed.

What was checked?

• 金額 = the amount, the price, the total

So:

• 金額を確認しました = checked the amount

This is a very standard object + を + verb pattern.

金額 means amount of money, total amount, or sum. In this sentence it likely means the total charge or billed amount.

Compared with 値段:

• 値段 = price of an item
• 金額 = monetary amount, often a total or stated sum

So if you are checking a receipt, bill, or total before paying, 金額 sounds very natural.

もう一度 means once more or one more time.

• もう = more / again
• 一度 = one time

So もう一度確認しました = checked once more

This is more specific than また, which often just means again in a broader sense.
もう一度 emphasizes repeating the action one extra time.

Compare:

• もう一度確認する = check one more time
• また確認する = check again

Both can work, but もう一度 is especially natural when you want to stress a deliberate re-check.

Because the sentence is describing a completed action.

• 確認します = check / will check
• 確認しました = checked

So the speaker is saying that before paying, they checked the amount once more.

The sentence is reporting something that already happened, so past tense is appropriate.

確認する means more than just to look at. It means to confirm, to verify, or to make sure.

So:

• 見ました = looked at it
• 確認しました = checked/confirmed it carefully

Since the speaker is checking the amount before payment, 確認しました is much more natural because it implies making sure the amount is correct.

Japanese often leaves out the subject when it is understood from context.

So even though English usually needs something like I checked the amount once more, Japanese often just says:

• 会計の前に、金額をもう一度確認しました。

The listener usually understands who did the action from the situation.
An explicit 私は is possible, but it is often unnecessary.

The basic structure is:

• 会計の前に = before checkout
• 金額を = the amount
• もう一度 = once more
• 確認しました = checked

Japanese word order is more flexible than English, especially before the verb, as long as the particles make the roles clear.

For example, these are close in meaning:

• 会計の前に、金額をもう一度確認しました。
• 会計の前に、もう一度金額を確認しました。

Both are natural. The verb usually stays at the end.

Yes. 確認しました is in the ます form, which is polite.

• dictionary form: 確認する
• polite non-past: 確認します
• polite past: 確認しました

So this sentence sounds appropriate in normal polite conversation or writing.

No. Normally Japanese is written without spaces:

会計の前に、金額をもう一度確認しました。

Spaces are often added in learning materials to make the parts easier to see. In real Japanese writing, you would usually not see those spaces.