Learn Hardcore Norwegian: Hvis renten stiger, blir det vanskeligere å nedbetale både lån og gjeld. - If the interest rate rises, it becomes harder to pay off both loans and debt.

Renten is the definite form (“the interest rate”), referring to a specific interest rate that’s already understood in context (often the general/official rate or your rate).
En rente would mean “an interest rate” in a more general, non-specific sense.

Why is there a comma after stiger?

Norwegian normally uses a comma between a subordinate clause and the main clause when the subordinate clause comes first:
Hvis renten stiger, (subordinate clause) blir det ... (main clause).

What’s the grammar of Hvis renten stiger—is it like English “if the rate rises”?

Yes. Hvis introduces a conditional subordinate clause. The word order inside that clause is straightforward: subject + verb:
renten (subject) + stiger (verb).

Why is the verb blir before det in blir det vanskeligere?

Because Norwegian has V2 word order in main clauses: the finite verb is in the second position.
When the sentence starts with the Hvis-clause, that whole clause counts as the first element, so the main clause must start with the verb:
Hvis …, blir det …
(Compare: Det blir vanskeligere … if the main clause stands alone.)

What does det refer to here? Is it “it”?

Here det is a dummy/expletive subject, like English “it” in “it becomes harder to…”. It doesn’t refer to a specific noun; it just fills the subject slot:
Det blir vanskeligere å ... = “It becomes harder to ...”

Why is vanskeligere used instead of vanskelig?

Vanskeligere is the comparative form: “more difficult / harder.”
It’s formed with -ere for many adjectives:
vanskelig → vanskeligere.

Why do we have å before nedbetale?

Å is the standard infinitive marker, like English “to”:
å nedbetale = “to pay down / to repay.”

What exactly does nedbetale mean, and could it be written differently?

Nedbetale means “to pay down” (typically gradually, in installments) or “to repay.”
A common alternative phrasing is betale ned (same idea, just written as a verb + particle).

Why does it say å nedbetale både lån og gjeld—what does både … og … do?

Både … og … means “both … and …” and links two items in a balanced way:
både lån og gjeld = “both loans and debt.”
You typically don’t put a comma between the two items.

Is there a difference between lån and gjeld?

Yes, though they overlap in everyday usage:

lån = a loan (a specific borrowed amount/product from a lender)
gjeld = debt (the total amount you owe, or debt in general)
So the phrase covers both the specific loans and the overall debt burden.

Why are the verbs in present tense (stiger, blir) if this is a conditional?

Norwegian often uses present tense for general conditions and predictable results, similar to English:
“If the rate rises, it becomes harder …”
You don’t need a future marker unless you want to emphasize the future.

Could Hvis be replaced with another word?

Yes. Dersom is a common more formal alternative meaning the same thing:
Dersom renten stiger, blir det vanskeligere …