Learn Hardcore Finnish: Varmistan, että leima on paperissa, ennen kuin lähden. - I make sure that the stamp is on the paper before I leave.

Finnish commonly uses the present tense for near-future or planned actions. Varmistan literally means I make sure / I ensure, and it can refer to something you do now as part of a plan before leaving. English often uses I’ll make sure, but Finnish typically keeps the present: Varmistan … ennen kuin lähden.

What does the ending -n in Varmistan and lähden mean?

The -n ending marks 1st person singular (I).

varmistaa → varmistan = I make sure
lähteä → lähden = I leave / I’m leaving
Finnish usually drops the subject pronoun minä because the verb ending already shows the person.

Why is there että after Varmistan?

että introduces a subordinate clause meaning that. It’s the standard way to express I make sure that X is true:

Varmistan, että leima on paperissa = I make sure that the stamp is on the paper.
Without että, the structure would usually change and can sound incomplete or more like casual shorthand.

Why is there a comma after Varmistan and before ennen kuin?

Finnish punctuation normally uses commas to separate subordinate clauses from the main clause. Here you have two subordinate clauses:
1) että leima on paperissa (that-clause)
2) ennen kuin lähden (before-clause)
So commas are used: Varmistan, että …, ennen kuin …

Is the word order fixed? Could I say it differently?

The meaning stays the same with a few common variations. For example:

Varmistan, että leima on paperissa ennen kuin lähden. (often written with just the first comma)
Ennen kuin lähden, varmistan, että leima on paperissa. (emphasizes the timing: Before I leave…)
Finnish word order is flexible, but commas and clause structure keep it clear.

Why is it leima on paperissa and not something like an object form?

Because this is a copular sentence with olla (to be): X is in Y. In such sentences, leima is the subject in the basic form (nominative). You’re not “doing” something to the stamp; you’re stating its location.

What case is paperissa, and why that one?

paperissa is in the inessive case (-ssa/-ssä), meaning in something (inside).

paperi = paper (or a document)
paperissa = in the paper / in the document
So leima on paperissa = the stamp is in/on the paper (Finnish uses the “inside/in” case even when English thinks of it as “on,” depending on context like a stamp on a document).

Could it be paperilla instead of paperissa?

Sometimes, depending on what you mean.

paperissa (inessive) suggests the stamp is in the document / on the document as part of it (common for official stamps on paperwork).
paperilla (adessive, -lla/-llä) means on / at the surface: on the paper (lying on top of it).
For an official stamp on paperwork, paperissa is very natural.

What does ennen kuin mean grammatically, and why is it followed by lähden?

ennen kuin means before (literally before than). It introduces a time clause, and Finnish uses a normal finite verb there:

ennen kuin lähden = before I leave
The verb is in the present (lähden) because Finnish often uses present in time clauses even when the meaning is future relative to the main situation.

Can I use ennenkuin as one word?

Both appear, but standard writing usually prefers ennen kuin as two words, especially in careful formal Finnish. You may still see ennenkuin in some texts, but ennen kuin is the safer choice.

Does leima mean a physical stamp, an imprint, or something else?

leima can mean:

a stamp (the mark on a document)
the imprint/mark made by stamping
more figuratively, a label/stigma in some contexts
In this sentence, with paperissa, it most naturally means the official stamp mark on/in the document.

Would Finnish ever use tarkistan instead of varmistan here?

Yes, and the nuance changes:

Varmistan, että … = I make sure / I ensure (focus on ensuring the condition is met)
Tarkistan, että … = I check / verify (focus on checking, not necessarily taking steps to fix it)
If you might need to take action to ensure the stamp is there, varmistan fits well. If you’re only verifying, tarkistan may be better.