Granica je važna.

Because granica is a feminine singular noun, and adjectives in Serbian must agree with the noun in gender, number, and usually case.

• važan = masculine singular
• važna = feminine singular
• važno = neuter singular

So:

• važan čovek = an important man
• važna granica = an important border/boundary
• važno pitanje = an important question

In Granica je važna, both granica and važna are feminine singular.

Je is the 3rd person singular present tense of biti (to be).

So:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is

In this sentence:

• Granica = the border / boundary
• je = is
• važna = important

So je is simply the word is.

It is in the nominative singular, because it is the subject of the sentence.

The basic dictionary form of the noun is also granica.

In Granica je važna, the structure is:

• Granica = subject, nominative
• je važna = predicate, is important

Serbian does not have articles like English a/an and the.

So Granica je važna can mean:

• The border is important
• A border is important
• Boundary is important (depending on context, though this sounds less natural in English)

The exact meaning depends on the situation and context.

Yes. Serbian word order is more flexible than English word order.

The neutral order is:

• Granica je važna.

But you may also hear:

• Važna je granica.

That version gives more emphasis to važna or can sound contrastive, like The important thing is the border or It is the border that is important, depending on context.

So both are grammatical, but they do not always sound equally neutral.

A rough pronunciation guide is:

• Granica ≈ GRA-nee-tsa
• je ≈ yeh
• važna ≈ VAZH-na

A few useful sound notes:

• c is pronounced like ts in cats
• j is pronounced like y in yes
• ž is pronounced like the s in measure

So the whole sentence sounds roughly like:

GRA-nee-tsa yeh VAZH-na

Yes. Granica can mean several related things, depending on context:

• a border between countries
• a boundary
• a limit
• even a more abstract line that should not be crossed

So Granica je važna could mean:

• The border is important
• The boundary is important
• The limit is important

For example, in a psychological or social context, it could refer to personal boundaries.

It can describe both things and people.

Examples:

• Važna odluka = an important decision
• Važna tema = an important topic
• Važna osoba = an important person

The form changes depending on the noun:

• važan čovek = an important man
• važna žena = an important woman
• važno dete = an important child

So in your sentence, važna matches the feminine noun granica.

Yes. Bitna is a very common alternative.

Both važna and bitna can mean important, but there is a slight nuance:

• važna = important, significant
• bitna = important, essential, relevant

In many everyday situations, they are interchangeable.

So:

• Granica je važna.
• Granica je bitna.

Both are natural. Sometimes bitna can feel a little closer to crucial or what matters.

Yes, absolutely. It is a complete and natural sentence.

It has everything it needs:

• Granica = subject
• je = verb
• važna = predicate adjective

Serbian often allows very short, complete sentences like this, especially when making a simple statement.

In standard Serbian, yes, in a normal present-tense statement like this, je is included:

• Granica je važna.

Leaving out je would usually sound ungrammatical in standard Serbian. This is different from some other Slavic languages where the present tense of to be may be omitted more often.

So for learners, the safe rule is:

• use je in sentences like this.