pureininzuu ha saki ni kakuninsuru ni kosita koto ha nai.

に越したことはない is a fixed grammar pattern meaning:

• there’s nothing better than ...
• it’s best to ...
• you can’t go wrong by ...
• it would be preferable to ...

So in this sentence, 確認するに越したことはない means something like it’s best to check or you should check if possible.

It often has the nuance that doing something is the safer, wiser, or more desirable choice.

Both can mean something similar, but the nuance is a little different.

• 確認したほうがいい = you should check
  • more direct advice
• 確認するに越したことはない = it’s best to check / there’s nothing better than checking
  • slightly more indirect
  • often sounds more like as a precaution, that would be the wise thing to do

So に越したことはない often feels like cautious advice rather than a straightforward instruction.

Yes. 越した is the past form of 越す, which literally means things like to go beyond, to exceed, or to surpass.

In に越したことはない, the literal idea is:

• there is nothing that surpasses doing X

From that, the natural English meaning becomes:

• nothing is better than doing X
• it’s best to do X

So this expression is idiomatic. You usually should not translate 越した word-by-word in normal use.

Because this pattern normally attaches to the plain form of a verb.

Examples:

• 早く行くに越したことはない = It’s best to go early.
• 予約しておくに越したことはない = It’s best to make a reservation beforehand.
• 確認するに越したことはない = It’s best to check.

So 確認する is just the standard form that fits this grammar pattern.

先に means beforehand, first, or in advance, depending on context.

In this sentence, it means something like:

• before doing anything else
• ahead of time
• in advance

So 先に確認する means to check beforehand.

A natural English paraphrase would be:

• It’s best to confirm the number of players in advance.

That は marks プレイ人数 as the topic of the sentence.

So the sentence is structured like:

• As for the number of players, it’s best to check beforehand.

This does not mean プレイ人数 is the direct object of 確認する in the strict grammatical sense here. It is being presented as the thing under discussion.

Japanese often uses は to introduce the topic even when English would just use a direct object.

That は is part of the fixed expression に越したことはない.

You should learn に越したことはない as one chunk.

The は here gives contrast/emphasis, and the whole phrase means:

• there is nothing better than ...
• it’s best to ...

So this second は is not the same kind of は as the topic marker after プレイ人数, even though it is written the same way.

Because the sentence is choosing to present プレイ人数 as the topic with は, not simply as the object with を.

If you focused just on the verb phrase, you might expect:

• プレイ人数を確認する = to confirm the number of players

But the actual sentence is:

• プレイ人数は先に確認するに越したことはない

That is more like:

• As for the number of players, it’s best to check beforehand.

So the object-like idea is still there semantically, but the sentence is framed topically.

It is read:

• プレイにんずう

人数 means number of people.

So プレイ人数 means number of players.

It is understandable, especially in game-related contexts, but depending on the situation, native speakers might also use things like:

• プレイ人数
• 参加人数 = number of participants
• 何人でプレイできるか = how many people can play
• 対応人数 = supported number of players

So プレイ人数 is not strange, but in real-world Japanese, the most natural wording can depend on the exact context.

Yes, it is understandable and basically natural.

That said, many native speakers might say something slightly more explicitly like:

• プレイ人数は先に確認しておくに越したことはない。
• プレイ人数は事前に確認しておいたほうがいい。

Why? Because 確認しておく often sounds especially natural for checking something in advance as preparation.

So your sentence is fine, but 確認しておく may feel even more natural in everyday usage.

確認する simply means to confirm / to check.

確認しておく means:

• to check in advance
• to make sure beforehand
• to check and have that done ahead of time

The 〜ておく part adds a preparation nuance.

So compare:

• プレイ人数を確認する = check the number of players
• プレイ人数を確認しておく = check the number of players beforehand, for future convenience/preparation

Since this sentence already has 先に, 確認する works, but 確認しておく can sound especially natural.

Yes. It can also be used with nouns and adjectives.

Examples:

• 安いに越したことはない。
  = Cheaper is better.

• 静かなに越したことはない。
  This is not correct.

For な-adjectives, you usually say:

• 静かなほうがいい or
• 静かであるに越したことはない
  = It’s best if it’s quiet.

For nouns:

• お金はあるに越したことはない。
  = It’s better to have money.

For い-adjectives:

• 早いに越したことはない。
  = Sooner is better.

So yes, the pattern is flexible, but the exact form depends on what comes before it.

It sounds a bit more polished and slightly more formal or written than very casual alternatives like:

• 〜したほうがいい
• 〜するといい
• 〜しておくといい

It is common in both speech and writing, but it has a somewhat thoughtful, advisory tone.

So in this sentence, it sounds like calm advice:

• It’s best to confirm that beforehand.

A useful breakdown is:

• プレイ人数は
  = as for the number of players

• 先に
  = beforehand / first

• 確認する
  = confirm

• に越したことはない
  = it’s best to / there’s nothing better than

So the skeleton is:

• X は Y する に越したことはない

Meaning:

• As for X, it’s best to do Y.

In this case:

• As for the number of players, it’s best to confirm it beforehand.

Yes, exactly.

That is one of the most important nuances of に越したことはない.

It usually does not sound like:

• you must do this

It more often sounds like:

• this is the better course of action
• it would be smart to do this
• if possible, this is preferable

So the sentence carries a mild, practical recommendation rather than a strict command.