Jantungnya tidak sihat.

Jantungnya breaks down as:

• jantung = heart
• -nya = his / her / its (and sometimes their, depending on context)

So jantungnya usually means his heart or her heart.

In context, the full sentence means something like His/Her heart is not healthy.

In Malay, possession is often shown by adding a suffix like -nya to the noun.

So instead of saying something structured like his heart, Malay can say:

• jantungnya = his/her heart

Another possible way is:

• jantung dia = his/her heart

Both are possible, but jantungnya is a very common and natural structure, especially in written or more formal Malay.

Here, -nya marks a third-person possessor:

• his
• her
• sometimes its

So jantungnya = his/her heart.

A useful thing to know is that -nya can do more than one job in Malay. In other sentences, it can also make something sound more definite, like the ..., but in this sentence the most natural reading is possessive: his/her heart.

Because tidak is used to negate:

• verbs
• adjectives

And sihat is an adjective meaning healthy / well.

So:

• tidak sihat = not healthy / unwell

By contrast, bukan is mainly used to negate:

• nouns
• noun phrases
• identity/equation sentences

For example:

• Dia bukan doktor. = He/She is not a doctor.

So in Jantungnya tidak sihat, tidak is the correct choice.

Sihat means healthy, well, or in good condition.

When talking about a body part, sihat means that it is healthy or functioning well. So:

• jantungnya sihat = his/her heart is healthy
• jantungnya tidak sihat = his/her heart is not healthy

With people, sihat can also mean well in a general health sense.

Malay often does not use a separate word for is/am/are in simple sentences like this.

So:

• Jantungnya sihat literally looks like heart-his healthy
• but it naturally means His/Her heart is healthy

This is very normal in Malay. English needs is, but Malay usually does not in sentences like this.

Yes. The order is completely normal:

• Jantungnya = his/her heart
• tidak sihat = not healthy

So the structure is basically:

• subject + negation + adjective

That is a very common Malay sentence pattern.

Yes. Jantung dia tidak sihat is also natural and means the same thing.

Compare:

• jantungnya = his/her heart
• jantung dia = his/her heart

Very roughly:

• jantungnya can sound a bit more compact, written, or formal
• jantung dia can sound more conversational

Both are correct.

Yes, sometimes -nya can make a noun sound definite, a bit like the in English.

But in this sentence, learners will usually understand jantungnya as his/her heart, because that is the most natural interpretation.

So while -nya can have more than one function in Malay, here the possessive reading is the one you should focus on first.

Usually, yes, it refers to health or physical condition, but the exact nuance depends on what is being described.

For example:

• Dia tidak sihat. = He/She is unwell
• Jantungnya tidak sihat. = His/Her heart is unhealthy / not functioning well

With jantung specifically, it suggests a heart problem or that the heart is not in a healthy condition.

A very common casual change is using tak instead of tidak:

• Jantungnya tak sihat.

This means the same thing, but sounds less formal.

So:

• tidak = standard/formal
• tak = casual/spoken

Both are very common in real life.

A simple pronunciation guide is:

• jantungnya ≈ jan-toong-nya
• tidak ≈ tee-dahk
• sihat ≈ see-haht

A few helpful notes:

• ng in jantung is like the sound in English sing
• ny in -nya is like the ny in Spanish señor or the ni in onion
• in casual speech, tidak is often shortened to tak

So you may often hear:

• Jantungnya tak sihat.

Yes. Both are possible, depending on context.

Possible English renderings include:

• His heart is not healthy.
• His heart is unhealthy.
• His heart is not well.
• He has a heart problem. (more interpretive, less literal)

The exact best translation depends on the context, but the Malay sentence itself is straightforward: it says the heart is not healthy.