Tento park je ještě hezčí na jaře.

Tento means this.

So tento park = this park.

It agrees with park in:

• gender: masculine inanimate
• number: singular
• case: nominative

In everyday speech, Czech also often uses tenhle for this, but tento is a standard and very common form.

Because park is:

• masculine inanimate
• singular
• the subject of the sentence, so it is in the nominative case

The nominative singular masculine inanimate form of tento is tento.

A learner often benefits from seeing the agreement clearly:

• ten park = that/the park in some contexts
• tento park = this park

Czech demonstratives change form depending on the noun they describe.

Je is the 3rd person singular form of the verb být = to be.

So here:

• park je hezčí = the park is prettier

Because the subject is singular (park), Czech uses je.

Yes. Hezčí is the comparative form of hezký or hezká/hezké, meaning pretty / nice / գեղեցी-looking depending on context.

So:

• hezký = pretty / nice
• hezčí = prettier / nicer

In this sentence, hezčí means prettier.

The form is not made by simply adding one ending the way English adds -er. Czech comparatives often involve a stem change, so this is something you mostly learn as a form:

• hezký → hezčí

Here ještě means even.

So:

• ještě hezčí = even prettier

That is a very common use with comparatives:

• ještě lepší = even better
• ještě horší = even worse
• ještě větší = even bigger

Be careful: ještě can also mean still or yet in other contexts. Here, because it comes before a comparative adjective, the meaning is even.

Because Czech, like English, can leave that comparison implied.

Ještě hezčí often means:

• even prettier than before
• even prettier than usual
• even prettier at that time

So the full logical idea is something like:

• This park is even prettier in spring.

The comparison is understood from context, just as in English.

Because Czech uses prepositions idiomatically, and they do not always match English one-to-one.

For the seasons, Czech commonly says:

• na jaře = in spring
• v létě = in summer
• na podzim = in autumn
• v zimě = in winter

So you cannot always predict the preposition from English. You usually need to learn the whole expression as a chunk.

Here, na jaře is simply the normal Czech way to say in spring.

Jaře is the locative singular of jaro = spring.

The preposition na can take different cases depending on meaning. Here it expresses time in the idiomatic phrase na jaře, so the noun appears in the locative.

So:

• dictionary form: jaro
• in this phrase: na jaře

This is a good example of why it helps to memorize preposition + case together.

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

The sentence:

• Tento park je ještě hezčí na jaře.

could also be rearranged, for example:

• Na jaře je tento park ještě hezčí.

Both are natural, but the emphasis changes a little.

• Tento park je ještě hezčí na jaře.
  Neutral statement; the final na jaře adds the time idea.

• Na jaře je tento park ještě hezčí.
  Puts more emphasis on in spring.

Czech uses word order partly for information structure, not only grammar.

Yes. Park is in the nominative singular because it is the subject of the sentence.

You can see the basic structure as:

• Tento park = subject
• je = verb
• ještě hezčí = predicate adjective/comparative description
• na jaře = time expression

So park stays in the basic dictionary form here.

Yes, but the meaning changes slightly.

• Tento park = this park
• Ten park usually means that park

So if you want to point to a park near you or one currently in focus as this park, tento park is the better choice.

In casual Czech, speakers may sometimes rely heavily on context, but for a learner it is best to keep the distinction:

• tento = this
• ten = that / sometimes a general demonstrative

Jaře is pronounced approximately like ya-rzhe.

The tricky sound is ř, which is unique to Czech. It is somewhat like a mix of:

• r
• and the zh sound in measure

You do not need perfect pronunciation immediately, but it helps to know that ř is a special Czech sound, not just a normal r.

So:

• j in Czech sounds like English y
• jaře begins roughly ya-
• ře contains that special ř sound

A rough learner-friendly approximation is YA-rzheh, though the real Czech sound is more precise than that.