Smalțul este sensibil.

Because -ul is the Romanian definite article attached to the end of the noun.

• smalț = enamel
• smalțul = the enamel

Romanian usually puts the definite article after the noun, unlike English, which puts the before it.

Romanian often uses the definite form when speaking about something in a general or class-wide sense, especially in statements like this.

So Smalțul este sensibil can mean:

• The enamel is sensitive
• or more naturally in English, depending on context, Enamel is sensitive

This is one of those places where Romanian and English do not match word-for-word in article use.

Este is the 3rd person singular of the verb a fi (to be), so it means is.

• smalțul = the enamel
• este = is
• sensibil = sensitive

Romanian normally keeps the verb to be in this kind of sentence, so you cannot simply leave it out.

Yes. E is a very common shorter form of este in everyday Romanian.

So both are possible:

• Smalțul este sensibil.
• Smalțul e sensibil.

The version with este may sound a little more neutral or formal, while e is very common in speech.

Because the adjective has to agree with the noun.

Smalț is a neuter noun in Romanian. Neuter nouns behave:

• like masculine in the singular
• like feminine in the plural

Since smalțul is singular, the adjective takes the masculine singular form:

• sensibil = masculine/neuter singular
• sensibilă = feminine singular

That is why Smalțul este sensibil is correct.

It looks similar, but here it means sensitive, not sensible.

This is a useful vocabulary warning:

• Romanian sensibil = sensitive
• English sensible = Romanian rezonabil, cu bun-simț, or similar depending on context

So sensibil is a bit of a false friend for English speakers.

A useful approximation is:

• smalț ≈ smalts
• smalțul ≈ SMAL-tsul

Important detail:

• ț is pronounced like ts, as in the end of cats

So the word is not pronounced like English smaltz with a z sound, but with a clear ts sound.

Ț is a separate Romanian letter, not just a decorated t.

It represents the sound ts.

Examples:

• țară = country
• puțin = a little
• smalț = enamel

So when you see ț, think ts.

Yes, but Smalțul este sensibil is the most normal, neutral order.

Romanian word order is somewhat flexible, but changing it usually adds emphasis or sounds marked. For example:

• Smalțul este sensibil. = neutral
• Este sensibil smalțul. = more marked, unusual without a special context

For a learner, the standard order is the safest choice.

For the negative, add nu before the verb:

• Smalțul nu este sensibil. = The enamel is not sensitive.

For a yes/no question, Romanian often keeps the same word order, and intonation does the job in speech:

• Smalțul este sensibil? = Is the enamel sensitive?

You may also see:

• Este smalțul sensibil?

That is also possible, especially in writing or more formal questioning.

Not always. Smalț can also mean enamel or glaze in other contexts, such as a coating on objects or ceramics.

So the exact meaning depends on context:

• in dentistry: tooth enamel
• in crafts/materials: enamel/glaze

In Smalțul este sensibil, many learners would understand it as tooth enamel if the context is about teeth or dental care.