אני לא בטוח אם המספר הזה נכון.

A very literal breakdown is:

• אני = I
• לא = not
• בטוח = sure / certain
• אם = if / whether
• המספר = the number
• הזה = this
• נכון = correct / right

So the sentence is literally:

I am not sure whether this number is correct.

A natural English translation is:

I’m not sure if this number is correct.

בטוח can mean both safe and sure/certain, depending on context.

In this sentence, אני לא בטוח means:

• I’m not sure
• I’m not certain

It does not mean I’m not safe here, because the rest of the sentence clearly shows that the speaker is talking about uncertainty, not danger.

Because בטוח is the masculine singular form.

Hebrew adjectives often agree with the gender and number of the person or thing they describe. Since בטוח describes the speaker after אני, the form depends on who is speaking:

• אני לא בטוח = said by a male speaker
• אני לא בטוחה = said by a female speaker

So if a woman says this sentence, she would normally say:

אני לא בטוחה אם המספר הזה נכון.

Here, אם means if or whether.

In this sentence, it introduces an indirect yes/no question:

• אם המספר הזה נכון = whether this number is correct

This is very common after expressions like:

• אני לא יודע אם... = I don’t know if...
• אני לא בטוח אם... = I’m not sure if...
• בדקתי אם... = I checked whether...

So אם here does not mean mother, even though the same spelling can also mean mother in other contexts.

Both structures exist in Hebrew, but they mean different things.

• המספר הזה = this number
• זה המספר = this is the number or this is the number one

In your sentence, the noun phrase is this number, so Hebrew uses:

• המספר הזה

A key pattern in Hebrew is that this/that usually comes after the noun:

• הספר הזה = this book
• הבית הזה = this house
• המספר הזה = this number

Also, the noun usually takes ה־ when using הזה / הזאת / האלה:

• ספר = a book
• הספר הזה = this book

Because Hebrew normally makes both parts definite in expressions like this number.

So:

• מספר = a number
• המספר הזה = this number

This is the usual Hebrew structure:

• הילד הזה = this boy
• המכונית הזאת = this car
• האנשים האלה = these people

So even though English says this number without the, Hebrew uses the definite article ה־ with the noun.

Because נכון agrees with המספר, and מספר is a masculine singular noun.

So:

• מספר is masculine singular
• therefore the adjective is נכון

Examples:

• המספר הזה נכון = This number is correct
• התשובה הזאת נכונה = This answer is correct

Since תשובה is feminine, the adjective becomes נכונה.

Here נכון means:

• correct
• right
• accurate

So המספר הזה נכון means this number is correct.

In other contexts, נכון can also mean things like:

• true
• right as in That’s right
• sometimes proper / appropriate, depending on context

But in this sentence, correct is the best meaning.

A common pronunciation guide is:

Ani lo batuaḥ im ha-mispar ha-ze na-khon.

A slightly smoother version in connected speech:

Ani lo batuaḥ im hamispar haze nakhon.

Some notes:

• אני = a-NEE
• לא = loh
• בטוח = ba-TOO-aḥ
• אם = im
• המספר = ha-mis-PAR
• הזה = ha-ZEH
• נכון = na-KHON

The ḥ sound in בטוח is the throaty Hebrew ח sound.

Yes, this is a very natural sentence.

Hebrew often builds this kind of sentence as:

• אני לא בטוח אם...
• I’m not sure if...

Then comes the clause:

• המספר הזה נכון
• this number is correct

So the full structure is:

• statement of uncertainty
• followed by an if/whether clause

This is standard and very common.

Usually, you would keep אני here.

Hebrew verbs often show person, so subjects can sometimes be omitted. But in this sentence there is no finite verb meaning am; Hebrew often leaves out the present-tense to be. Because of that, אני helps clearly show who the subject is:

• אני לא בטוח = I’m not sure

Without אני, לא בטוח can still appear in conversation, but it sounds more fragment-like, like:

• Not sure
• Not certain

That can be natural in casual speech, but the full sentence normally includes אני.

Yes. It is completely normal and natural.

It sounds clear and standard. A native speaker might also say similar versions such as:

• אני לא בטוח שזה נכון. = I’m not sure that this is correct.
• אני לא בטוח שהמספר הזה נכון. = I’m not sure this number is correct.

But your original sentence is perfectly good Hebrew.

The adjective at the end would change to match the noun.

For example, with תשובה = answer, which is feminine:

• אני לא בטוח אם התשובה הזאת נכונה.
• I’m not sure if this answer is correct.

Notice the agreement:

• התשובה = feminine noun
• הזאת = feminine this
• נכונה = feminine correct

So in Hebrew, words like this and correct often change form to match the gender of the noun.