La decisión fue suya.

Because suya has to agree with la decisión, which is feminine singular.

In Spanish, possessive pronouns like mío, tuyo, suyo, nuestro change to match the noun they refer to:

• el libro es suyo
• la decisión es suya
• los libros son suyos
• las decisiones son suyas

So here, since decisión is feminine singular, the correct form is suya.

Here, suya is a possessive pronoun. It means something like his/hers/yours/theirs, depending on context.

It stands in for a longer phrase such as:

• de él
• de ella
• de usted
• de ellos
• de ellas
• de ustedes

So La decisión fue suya literally has the structure The decision was his/hers/yours/theirs.

Spanish usually uses the definite article more often than English.

In this sentence, la decisión refers to a specific decision already known from the context, so la is natural.

Compare:

• La decisión fue suya = The decision was his/hers...
• Una decisión fue suya would mean One decision was his/hers..., which sounds different and much less likely in this context.

Both can be possible, but they give a different feel.

• fue presents it as a completed fact or a specific conclusion in the past.
• era sounds more like background information, description, or an ongoing past situation.

So:

• La decisión fue suya = the speaker is identifying who made the decision, often as a finished fact.
• La decisión era suya = this could mean something more like the decision was in her hands or the decision belonged to her in an ongoing situation.

In many real contexts, fue suya is the more natural choice when assigning responsibility for one particular decision.

Yes, but only in the right context.

Use era suya when you want to describe a past situation rather than point to a finished event. For example:

• En aquel momento, la decisión era suya.
  At that moment, the decision was hers / it was up to her.

Use fue suya when you mean something more like:

• In the end, it was her decision.
• She was the one who made the decision.

So the difference is not about correctness alone, but about how the speaker sees the situation.

You can say su decisión, but it means something slightly different.

• su decisión = his/her/their decision as a noun phrase
• la decisión fue suya = the decision was his/hers/theirs

Compare:

• Su decisión fue arriesgada.
  His/Her decision was risky.
• La decisión fue suya.
  The decision was his/hers.

The version with fue suya puts more emphasis on who the decision belonged to / who was responsible for it.

Not necessarily. In sentences like this, it often suggests responsibility, authorship, or control, not just simple ownership.

So La decisión fue suya often implies:

• She made the decision
• It was his call
• They were responsible for deciding

That is why this structure is very common when talking about blame, credit, or authority.

Yes. Suya can mean several things depending on context:

• his
• hers
• your (formal singular)
• their
• your (formal plural)

Spanish often leaves this to context.

If you need to be clearer, you can say:

• La decisión fue de él
• La decisión fue de ella
• La decisión fue de usted
• La decisión fue de ellos

These are especially useful when there could be confusion.

Yes, absolutely.

Both are correct, but they are used a little differently:

• La decisión fue suya sounds smoother and more compact.
• La decisión fue de ella is more explicit and helps remove ambiguity.

So if the context already makes it clear who suya refers to, the possessive pronoun is very natural. If not, de ella, de él, etc. may be better.

The stress falls on the first syllable: SU-ya.

It is pronounced as two syllables:

• su-ya

In standard Spanish from Spain, the y sound is similar to the y in yes, though exact pronunciation can vary a bit by region.

La decisión fue suya is the normal and most neutral order.

You might also hear variations for emphasis, such as:

• Suya fue la decisión

This is more literary or emphatic, and not the default word order for everyday speech.

For most learners, the standard pattern to remember is:

• [definite article + noun] + [ser] + [possessive pronoun]

For example:

• El error fue mío
• La culpa fue tuya
• La idea fue nuestra
• La decisión fue suya