qǐng búyào gàosu biéren zhège mìmì.

Yes, 请 here works very much like please in English. It makes the request more polite.

In 请不要告诉别人这个秘密, 请 softens the command:

• 不要告诉别人这个秘密。 = Don’t tell others this secret.
• 请不要告诉别人这个秘密。 = Please don’t tell others this secret.

A useful thing to know is that 请 can also mean to invite or to treat someone in other contexts, but in this sentence it simply means please.

Because 不要 + verb is a very common way to say don’t do something.

So:

• 不要告诉 = don’t tell
• 不要说 = don’t say
• 不要走 = don’t leave

If you only used 不告诉, it would usually sound more like a statement about habit or future action, such as I won’t tell, rather than a direct request or prohibition.

Compare:

• 我不告诉他。 = I won’t tell him.
• 不要告诉他。 = Don’t tell him.

So in this sentence, 不要 is the correct pattern for a negative request.

This is because of tone sandhi.

Normally, 不 is fourth tone: bù.
But when 不 comes before another fourth-tone syllable, it changes to second tone.

Since 要 is fourth tone (yào), 不 + 要 is pronounced:

• búyào

Other examples:

• 不是 → búshì
• 不要 → búyào
• 不对 → búduì

So the character stays 不, but the pronunciation changes.

Yes, absolutely. 请别告诉别人这个秘密 is natural and common.

Both 不要 and 别 can be used for don’t in commands:

• 请不要告诉别人这个秘密
• 请别告诉别人这个秘密

A rough comparison:

• 不要 can sound a little more explicit or formal.
• 别 is often shorter and a bit more conversational.

In everyday speech, many people would naturally say:

• 别告诉别人。
• 请别告诉别人这个秘密。

So your sentence with 不要 is correct, but 别 is also a very common alternative.

No. In 别人, the word 别 does not mean don’t.

Here, 别人 is a fixed word meaning:

• other people
• someone else

So:

• 告诉别人 = tell other people / tell someone else

This is important because 别 has different meanings in different words and structures:

• 别说话！ = Don’t talk! → here 别 means don’t
• 别人 = other people → here 别人 is one vocabulary item

So in your sentence, think of 别人 as one whole word.

Because with 告诉, Chinese often uses the order:

告诉 + person + thing

So:

• 告诉别人这个秘密
• literally: tell other people this secret

This is similar to English tell someone something.

Examples:

• 告诉我真相。 = Tell me the truth.
• 告诉他这个消息。 = Tell him this news.
• 不要告诉别人这个秘密。 = Don’t tell other people this secret.

Chinese can also use other patterns, but this one is very standard and natural with 告诉.

Because in Mandarin, when a demonstrative like 这 or 那 comes before a noun, you usually need a measure word.

The pattern is:

这 / 那 + measure word + noun

So:

• 这个秘密 = this secret
• 那个人 = that person
• 这本书 = this book

Here, the measure word is 个, which is the most common general measure word.

So 这个秘密 is the normal structure.
这秘密 would sound incomplete or unnatural in standard Mandarin.

Because 的 is not used between a demonstrative phrase and the noun in this kind of structure.

The normal pattern is:

• 这个秘密
• 那个地方
• 这本书

Not:

• 这个的秘密 ✘

的 is used in many modifier structures, but not here.

For example:

• 我的秘密 = my secret
• 重要的秘密 = an important secret
• 这个秘密 = this secret

So 这个秘密 is already complete without 的.

In careful dictionary-style citation, it is often given as gàosù.
But in everyday speech, the second syllable is very often pronounced with a neutral tone:

• gàosu

So learners will commonly hear both represented, but in natural spoken Mandarin, gàosu is extremely common.

That means:

• first syllable: gào — fourth tone
• second syllable: often lighter, less stressed

This kind of tone reduction is very common in spoken Chinese.

It is natural and polite enough, especially because it includes 请.

• 请不要告诉别人这个秘密。 sounds like a polite request.
• Without 请, it becomes more direct: 不要告诉别人这个秘密。
• With 请 plus a softer tone of voice, it sounds courteous.

That said, depending on the situation, native speakers might also say:

• 请别告诉别人这个秘密。
• 这件事请不要告诉别人。
• 请帮我保密。 = Please keep it confidential / Please keep it secret.

So your sentence is correct and natural, but there are other equally natural ways to express the same idea.

Yes. 秘密 basically means secret, but the exact English translation depends on context.

It can refer to:

• a personal secret
• hidden information
• something not meant to be shared

In this sentence, 这个秘密 most naturally means this secret.

Examples:

• 这是一个秘密。 = This is a secret.
• 不要把秘密告诉别人。 = Don’t tell others the secret.

So in your sentence, 秘密 is used in a very normal, everyday way.

Yes, but the sentence structure would change.

The original is:

• 请不要告诉别人这个秘密。

A very natural alternative is:

• 请不要把这个秘密告诉别人。

This uses the 把 construction:

• 把这个秘密告诉别人 = tell this secret to others

Both are correct. The difference is mainly in structure and emphasis:

• 告诉别人这个秘密 = straightforward tell others this secret
• 把这个秘密告诉别人 = puts more focus on this secret as the thing being handled

For learners, the original version is simpler and very useful.

A natural rhythm would be something like:

请 / 不要告诉别人 / 这个秘密。

or

请不要 / 告诉别人 / 这个秘密。

Usually, 别人 and 这个秘密 are both important pieces of information:

• 别人 = who should not be told
• 这个秘密 = what should not be told

In normal speech, 请 is usually lighter, and the main content words carry more weight:

• 请 búyào gàosu biéren zhège mìmì.

So if you say it smoothly and don’t over-stress every syllable, it will sound more natural.