Za předpokladu, že správce potvrdí dostupnost, rezervujeme společenskou místnost.

It is a fixed expression meaning provided that / on the assumption that. It is close in meaning to pokud, but it sounds more formal and more typical of written, administrative, or business Czech.

Compare:

• Pokud správce potvrdí dostupnost... = neutral, everyday
• Za předpokladu, že správce potvrdí dostupnost... = more formal, more official

So the sentence has a slightly formal tone.

Because předpokladu is the genitive singular form of předpoklad.

• nominative: předpoklad
• genitive: předpokladu

In the fixed phrase za předpokladu, Czech uses this genitive form. It is best to learn za předpokladu, že as one whole chunk.

Czech uses commas to separate subordinate clauses.

In this sentence:

Za předpokladu, že správce potvrdí dostupnost, rezervujeme společenskou místnost.

• the first comma comes before že
• the second comma closes the subordinate clause before the main clause continues

So the structure is:

Za předpokladu, že ... , rezervujeme ...

This is normal Czech punctuation.

That is because potvrdí is the present form of a perfective verb: potvrdit.

In Czech, the present forms of perfective verbs often refer to the future. So here:

• potvrdí = will confirm

It does not mean an ongoing present action. It means a completed future action: first the manager confirms availability, then the reservation happens.

Because the sentence refers to one completed act of confirmation.

The logic is:

1. the manager confirms availability
2. then the room is reserved

That fits the perfective verb potvrdit very well.

If you used potvrzuje, it would sound more like:

• he is confirming it right now
• he confirms it regularly
• the action is ongoing or repeated

That is not the idea here.

Rezervujeme is the present tense of the imperfective verb rezervovat, but here it can sound like a procedural present: it states what we do in that situation.

So in English, you would often translate it as we will reserve even though Czech uses the present form.

A useful nuance:

• rezervujeme = somewhat procedural, policy-like, or planned
• zarezervujeme = more clearly a single completed future action

So yes, zarezervujeme would also be possible in many contexts, but the original rezervujeme sounds natural if the sentence is stating a rule or procedure.

Because Czech usually leaves out subject pronouns when the verb ending already makes the subject clear.

The ending -me in rezervujeme tells you that the subject is we.

So:

• rezervujeme = we reserve / we will reserve

You would only add my if you want emphasis or contrast:

• My rezervujeme společenskou místnost. = We reserve the room.

Because it is the direct object of rezervujeme, so it is in the accusative singular.

• společenská → společenskou
• místnost → místnost

The noun místnost has the same form in nominative and accusative singular, but the adjective changes, so the case is visible mainly on společenskou.

Yes. Czech word order is flexible, and changing it mainly changes emphasis.

For example:

• Za předpokladu, že správce potvrdí dostupnost, rezervujeme společenskou místnost.
  Neutral, formal order.
• Společenskou místnost rezervujeme za předpokladu, že správce potvrdí dostupnost.
  Puts more focus on the room.
• Za předpokladu, že správce potvrdí dostupnost, společenskou místnost rezervujeme.
  Slightly more contrastive or deliberate.

The original version is a very natural formal wording.

Yes. That would be a perfectly normal alternative:

Pokud správce potvrdí dostupnost, rezervujeme společenskou místnost.

This version is less formal and more straightforward.

But you normally do not combine the two patterns like this:

• za předpokladu, že ... = correct
• pokud ... = correct
• za předpokladu, pokud ... = not standard

So choose one structure or the other.

Yes. Czech formal style often prefers an abstract noun such as dostupnost instead of a longer clause.

So these are similar in meaning:

• správce potvrdí dostupnost
• správce potvrdí, že je místnost dostupná
• správce potvrdí, že je místnost volná

The version with dostupnost is more compact and slightly more official in tone.