Learn Hardcore Spanish (Spain): Aceptar una disculpa sincera puede cerrar un conflicto antiguo. - Accepting a sincere apology can close an old conflict.

Aceptar una disculpa sincera is functioning as the subject of the sentence.
→ Roughly: “Accepting a sincere apology” / “To accept a sincere apology”.

Because that whole phrase is the subject, the verb that follows is in 3rd person singular:

Aceptar una disculpa sincera puede cerrar…
Aceptar (that action) = it → puede (3rd person singular).

You cannot conjugate aceptar here (Aceptas una disculpa sincera puede cerrar… is wrong), because then you’d have two finite verbs in a row without a proper structure.

Why is it puede cerrar and not just cierra? Could I say Aceptar una disculpa sincera cierra un conflicto antiguo?

Both are grammatically possible, but the nuance changes:

Aceptar una disculpa sincera puede cerrar un conflicto antiguo.
→ Accepting a sincere apology *can close an old conflict.
This expresses *possibility or potential: it may close it, but not always.
Aceptar una disculpa sincera cierra un conflicto antiguo.
→ Accepting a sincere apology closes an old conflict.
This sounds more like a general rule or law, almost always true.

So puede softens the statement and makes it sound less absolute and more realistic.

Why is it una disculpa and not something like un disculpo? What gender is disculpa?

Disculpa is a feminine noun, so it uses una:

una disculpa = a(n) apology
There is no noun disculpo in standard Spanish.

It comes from the verb disculpar (to excuse / to pardon), but the noun form is la disculpa:

Pedir disculpas – to apologize / to say sorry
Aceptar una disculpa – to accept an apology
La disculpa fue sincera. – The apology was sincere.

What’s the difference between disculpa, perdón, and expressions like lo siento or perdóname?

They’re all related to apologizing, but used slightly differently:

disculpa / disculpas
Noun(s): “apology / apologies.”
- Pedir disculpas – to apologize.
- Aceptar una disculpa sincera – to accept a sincere apology.
perdón
Noun or interjection: “pardon,” “forgiveness,” or “sorry.”
- As a quick “sorry” in everyday speech: Perdón, no te vi.
- As a noun: Pedir perdón – to ask for forgiveness.
lo siento
Literally “I feel it” → “I’m sorry” (expressing regret).
- Lo siento mucho. – I’m very sorry.
perdóname / perdona / perdone
Imperative forms of perdonar (to forgive), used like “forgive me” or “excuse me.”
- Perdóname, llegué tarde. – Forgive me, I was late.
- Perdona / Perdone – excuse me (informal/formal).

In your sentence, una disculpa sincera is specifically “a sincere apology” (the thing that is being accepted).

Why do the adjectives go after the nouns in disculpa sincera and conflicto antiguo? Could I say sincera disculpa or antiguo conflicto?

The default position for descriptive adjectives in Spanish is after the noun:

una disculpa sincera – a sincere apology
un conflicto antiguo – an old conflict

Putting the adjective before the noun is possible, but it usually adds a nuance of emphasis, subjectivity, or a more literary/poetic tone:

una sincera disculpa
→ Highlights the sincerity more; sounds a bit more emotional or rhetorical.
un antiguo conflicto
→ Very common; often means “an old, long‑standing, or former conflict.”

With antiguo, position can also affect meaning:

un antiguo alumno = a former student
un alumno antiguo = an old (aged) student (and sounds odd).

For conflicto, both un antiguo conflicto and un conflicto antiguo are understood as a conflict from long ago, but un antiguo conflicto is a little more idiomatic and common in written or formal Spanish.

Is there a difference between antiguo and viejo when they both mean “old”?

Yes, there are nuances:

antiguo
- Often used for things that are old in time, former, or from long ago.
- Sounds a bit more neutral or formal.
- un conflicto antiguo / un antiguo conflicto – an old/long‑standing conflict.
viejo
- Used for old in age, especially people or physical objects.
- Can sometimes sound a bit negative or informal.
- un libro viejo – an old (worn-out) book.
- un hombre viejo – an old man (aged).

Position also matters:

un viejo amigo – a long‑time friend (not necessarily old in age).
un amigo viejo – a friend who is old (aged).

In your sentence, antiguo is the better choice because conflicto is something abstract and we’re talking about it being long‑standing, not “old and worn out.”

Is cerrar un conflicto a natural expression in Spanish? Could I say resolver or zanjar instead?

Yes, cerrar un conflicto is natural and quite common. It’s similar to English “to close a conflict” in the sense of bringing it to an end.

Other common verbs with conflicto are:

resolver un conflicto – to resolve a conflict (focus on finding a solution).
zanjar un conflicto – to settle a conflict (often definitively), more formal/literary.
poner fin a un conflicto – to put an end to a conflict.

Your sentence:

Aceptar una disculpa sincera puede cerrar un conflicto antiguo.

could also be rephrased as:

…puede resolver un conflicto antiguo.
…puede poner fin a un conflicto antiguo.

All are correct; cerrar is quite idiomatic here.

Why is it una disculpa sincera and un conflicto antiguo instead of la disculpa sincera and el conflicto antiguo?

Using una / un (indefinite articles) makes the sentence general, about any sincere apology and any old conflict:

Aceptar una disculpa sincera puede cerrar un conflicto antiguo.
→ Accepting a sincere apology can close an old conflict (in general).

If you use la / el, you’re usually talking about specific things already known in the context:

Aceptar la disculpa sincera puede cerrar el conflicto antiguo.
→ Accepting the sincere apology can close the old conflict (that we both know about).

So the original sentence is more like a general statement or piece of advice.

How do I mention who the apology is from? Do I say aceptar una disculpa de alguien or use another preposition?

You use de to indicate who the apology comes from:

Aceptar una disculpa sincera de alguien puede cerrar un conflicto antiguo.
– Accepting a sincere apology from someone can close an old conflict.

With a specific person:

Aceptar una disculpa sincera de Juan puede cerrar un conflicto antiguo.
Aceptó la disculpa de su hermano.

You do not say aceptar una disculpa a alguien in this sense. A is used for the person you forgive (perdonar a alguien), not for the origin of the apology:

Perdonar a alguien – to forgive someone.
Aceptar la disculpa de alguien – to accept someone’s apology.

How would I say “By accepting a sincere apology, you can close an old conflict” more explicitly in Spanish?

Two natural options:

Impersonal/“one can” style:
- Al aceptar una disculpa sincera, se puede cerrar un conflicto antiguo.
  → By accepting a sincere apology, one can close an old conflict.
Direct “you” (informal singular):
- Al aceptar una disculpa sincera, puedes cerrar un conflicto antiguo.
  → By accepting a sincere apology, you can close an old conflict.

The construction al + infinitive means “on doing X / by doing X / when you do X.”

In Spain, would people more often say una disculpa or las disculpas in this kind of idea?

In Spain, both are understood, but you’ll very often see the plural with the set phrase pedir disculpas / aceptar las disculpas:

Pedir disculpas – to apologize (literally “to ask for apologies”).
Aceptar las disculpas de alguien puede cerrar un conflicto antiguo.
→ Accepting someone’s apologies can close an old conflict.

Your original sentence with una disculpa sincera is perfectly correct and natural; using the plural just reflects another very common pattern in Peninsular Spanish.