Learn Hardcore Indonesian: Untuknya, puasa juga bukan berarti melemahkan badan, tetapi cara melatih kesabaran. - For her/him, fasting also does not mean weakening the body, but a way to train patience.

untuknya feels a bit more compact and natural in written Indonesian.
In this type of opening phrase (Untuknya, …), untuknya is very common to introduce someone’s perspective or opinion.

So you can read it as:
“For him/her, fasting also does not mean weakening the body, but (it is) a way to train patience.”

Why is there a comma after Untuknya?

The comma marks “Untuknya” as an introductory phrase that sets the point of view:

Untuknya, … = “For him/her, …” / “From his/her perspective, …”

Placing it at the beginning and separating it with a comma is similar to English:

“For him, fasting doesn’t mean weakening the body …”
“In her view, fasting is not about weakening the body …”

You could also put it later in the sentence (Puasa, untuknya, juga bukan berarti…), but the given order with the comma at the start is very natural and clear in writing.

Is puasa being used as a noun or a verb here? Why is it not berpuasa?

In this sentence puasa functions like a noun (“fasting”), the topic/subject of the sentence:

Puasa juga bukan berarti …
≈ “Fasting also does not mean …”

About forms:

puasa can behave like both a noun (“fasting, the fast”) and a bare verb (“to fast”).
berpuasa is a more explicitly verbal form, often a bit more formal: “to be fasting”.

Both are possible in many contexts, but here we are talking about “fasting” as a concept, so the bare puasa (as a noun-like subject) is very natural:

Puasa bukan berarti melemahkan badan
“Fasting does not mean weakening the body.”

What is the role of juga here, and where can it appear in the sentence?

juga means “also / too / as well”.

Here it modifies the statement about fasting:

Puasa juga bukan berarti melemahkan badan …
≈ “Fasting also does not mean weakening the body …”

It implies this is another point in addition to something mentioned before (maybe another benefit or meaning of fasting).

Typical positions:

Before the verb phrase or predicate, like here:
Puasa juga bukan berarti …
Or after the subject pronoun:
Dia juga tidak berpikir begitu. = “He also doesn’t think so.”

Putting juga elsewhere is usually either unnatural or changes emphasis, so the position in the sentence is quite standard.

Why is it bukan berarti and not tidak berarti?

Indonesian has two basic negators:

tidak negates verbs and adjectives.
bukan negates nouns and equative/identity statements, and is also used in certain fixed expressions.

Here, berarti literally means “to mean, to signify”, but the pattern bukan berarti … is a very common fixed expression that translates roughly as:

“does not necessarily mean …”
“does not mean that …”

So:

puasa juga bukan berarti melemahkan badan
≈ “fasting also does not (necessarily) mean weakening the body”

You will often see bukan berarti used exactly like this, even though, taken literally, you might expect tidak berarti. In normal usage:

tidak berarti is more like “has no meaning / is meaningless”.
bukan berarti is “does not mean (that) …” (introducing a clarification or contrast), as in this sentence.

What does melemahkan mean, and how is it formed?

melemahkan means “to weaken (something)”.

Morphology:

lemah = “weak” (adjective)
me- + lemah + -kan → melemahkan

The prefix me- and suffix -kan together often form a causative verb: “to make something become X”.

So:

lemah → “weak”
melemahkan → “to make (something) weak”, “to weaken”.

In the sentence:

melemahkan badan = “to weaken the body”

What does badan mean here, and how is it different from tubuh?

badan literally means “body”.

Common synonyms:

badan – very common, neutral; used in everyday speech.
tubuh – also “body”, but can sound slightly more formal or literary, and is very common in written language too.

In this context:

melemahkan badan = “to weaken the body”
You could say melemahkan tubuh, and it would still be correct and natural.

There is no big meaning difference here; it’s mostly style and habit. badan is perfectly natural in this kind of general health / physical context.

What is the function of tetapi here, and how is it different from tapi or namun?

tetapi means “but / however”. It introduces a contrast with the previous clause:

… bukan berarti melemahkan badan, tetapi cara melatih kesabaran.
“… does not mean weakening the body, but (it is) a way to train patience.”

Comparisons:

tetapi – standard, slightly more formal than tapi, very common in writing.
tapi – informal/colloquial version of “but”; widely used in speech.
namun – closer to “however / nevertheless”; usually at the beginning of a sentence or clause:
Namun, puasa bukan berarti…

So you could also see:

…, tetapi merupakan cara melatih kesabaran. (neutral/formal)
…, tapi itu adalah cara melatih kesabaran. (more colloquial)
Namun, puasa bukan berarti melemahkan badan; puasa adalah cara melatih kesabaran. (more formal, separate sentence)

How does cara melatih kesabaran work grammatically? Is cara like “way/method”?

Yes, cara means “way, method, manner”.

The structure is:

cara (way/method)
melatih (to train)
kesabaran (patience)

So cara melatih kesabaran literally is:

“a way (of) training patience”
“a method to train patience”

Grammar points:

melatih is a transitive verb: “to train (someone/something)”.
kesabaran is its object.

So the whole phrase cara melatih kesabaran is a noun phrase:

cara is the head noun,
melatih kesabaran is a verb phrase that modifies cara, similar to English “way to train patience.”

This is a very common and productive pattern in Indonesian:
cara + [verb phrase] = “a way to [do something]”
e.g. cara belajar bahasa = “a way to learn (a) language”

What does kesabaran mean exactly, and how is it formed from sabar?

sabar means “patient” (adjective) or “to be patient”.

kesabaran is the abstract noun “patience”.

Morphology:

sabar (adj/verb)
ke- + sabar + -an → kesabaran = “the quality of being patient”, “patience”.

The ke- -an circumfix often turns adjectives or verbs into abstract nouns:

adil (just) → keadilan (justice)
jujur (honest) → kejujuran (honesty)
sabar (patient) → kesabaran (patience)

So in the sentence, melatih kesabaran = “to train (one’s) patience”.

Whose patience is being trained in melatih kesabaran? Why isn’t it stated?

Indonesian often leaves out possessive pronouns (my, your, his, our, etc.) when the owner is clear from context.

melatih kesabaran literally: “to train patience”
In natural English: “to train one’s patience” / “to train your own patience”.

You could explicitly say:

melatih kesabaran diri sendiri – training one’s own patience
melatih kesabaran kita – training our patience

But it isn’t necessary. In context, it’s understood that this is about the person who is fasting training their own patience.