Este tramo es difícil.

Tramo usually means a stretch, section, or segment of something that has parts.

In Spain, it is commonly used for:

• a stretch of road
• a section of a route
• part of a journey, path, race, or even a text/process

So in this sentence, tramo suggests one section of a larger whole, not just a vague part.

Because tramo is a masculine singular noun.

The demonstrative adjective has to match the noun:

• este = this, masculine singular
• esta = this, feminine singular

Examples:

• este tramo
• esta parte

So the form is determined by the gender of tramo, not by the English word this.

Because este already works as a determiner, like this in English.

In Spanish, you normally do not put an article before a demonstrative adjective:

• este tramo
• esa calle
• aquella casa

Not:

• el este tramo

So este already does the job of specifying the noun.

Here, es is used because the sentence describes the stretch as being difficult by nature or as a characteristic.

• ser → for descriptions, characteristics, classification
• estar → for states, conditions, location, results

So:

• Este tramo es difícil = This section is difficult.

That is the most neutral and standard choice.

A learner may wonder whether está difícil is possible. In some varieties of Spanish, yes, people may say that to emphasize the current situation or how it feels at the moment. But for standard European Spanish in a general learning context, es difícil is the form to learn first.

Because many Spanish adjectives do not change form for masculine/feminine in the singular.

So you get:

• este tramo es difícil
• esta parte es difícil

The adjective difícil only changes for number, not gender:

• singular: difícil
• plural: difíciles

Examples:

• Este tramo es difícil.
• Estos tramos son difíciles.

Here it is a demonstrative adjective because it comes directly before a noun:

• este tramo

It is modifying tramo.

Compare that with a pronoun:

• Este es difícil. = This one is difficult.

In that sentence, este replaces the noun instead of describing it.

No. In modern standard Spanish, este is normally written without an accent, whether it is an adjective or a pronoun.

So:

• Este tramo es difícil.
• Este es difícil.

Older materials may sometimes show éste as a pronoun, but that is generally avoided now unless there is a real ambiguity and a writer wants to mark it.

The accent mark shows the stress: di-FÍ-cil.

Without the written accent, Spanish spelling rules would suggest a different stress pattern. The accent tells you that the stressed syllable is fí.

So the pronunciation is roughly:

• dee-FEE-seel in an English approximation

The c before i in Spain is pronounced like the th in thin, so in Spain it sounds closer to:

• dee-FEE-thil

In much of Latin America, it sounds more like:

• dee-FEE-seel

Yes, often you can, but the nuance changes slightly.

• tramo = a stretch/segment, especially of a road, route, path, process, etc.
• parte = part, more general

So parte is broader and less specific.
If you are talking about a road, trail, or route, tramo often sounds more natural and precise.

Yes, but Este tramo es difícil is the normal, neutral order.

Spanish usually follows:

• subject + verb + adjective/complement

Other orders are possible for emphasis, but they are less neutral:

• Difícil es este tramo. → literary or emphatic
• Este difícil tramo... → possible, but now difícil is directly modifying tramo, which can sound more stylistic

For everyday speech, Este tramo es difícil is the best model.

Everything has to agree in number:

• Este tramo es difícil.
• Estos tramos son difíciles.

Changes:

• este → estos
• tramo → tramos
• es → son
• difícil → difíciles

This is a useful pattern to remember for agreement in Spanish.

No. A native speaker might also say:

• complicado
• duro
• peligroso (if it is dangerous)
• empinado (if it is steep)
• técnico (especially for hiking, climbing, cycling, etc.)

But difícil is a very general and natural choice when you simply want to say the section is hard.

So:

• Este tramo es difícil = broad, standard, useful
• Este tramo es complicado = also common, sometimes a bit more like complicated/tricky