Como estaba enferma, no pudo confirmar su asistencia a la reunión de ayer.

Yes, como often means how or like, but at the beginning of a sentence it can also mean since or as.

In this sentence:

Como estaba enferma, no pudo confirmar su asistencia...

it means:

Since she was ill, she couldn’t confirm her attendance...

This use is common when giving a reason, especially when that reason is mentioned first.

Compare:

• Como estaba cansado, me fui pronto. = Since I was tired, I left early.
• ¿Cómo estás? = How are you?

So here, como is not asking a question. It is introducing the cause.

Estaba is the imperfect of estar, while estuvo is the preterite.

Here, estaba enferma describes a state or condition in the background: she was ill. Spanish often uses the imperfect for background information, descriptions, or ongoing states.

• Estaba enferma = she was ill / she was feeling ill
• Estuvo enferma = she was ill for a completed period of time, viewed more as a finished event

In this sentence, the illness is the circumstance that explains why she could not do something, so estaba sounds natural.

Because enferma agrees with the person being described, and that person is understood to be female.

Spanish adjectives usually change for gender:

• enfermo = ill, masculine
• enferma = ill, feminine

So:

• Como estaba enferma... = Since she was ill... (female)
• Como estaba enfermo... = Since he was ill... (male)

Spanish often leaves out the subject pronoun, so the adjective helps show who is being referred to.

Spanish often omits subject pronouns when they are clear from the verb form or the context. This is very normal.

So instead of:

• Como ella estaba enferma, ella no pudo...

Spanish naturally says:

• Como estaba enferma, no pudo...

The person is understood from context, and enferma also tells us the person is feminine.

Including ella is possible, but it would usually be for emphasis or contrast.

Pudo is the preterite of poder, and here it means was unable to / could not in a specific situation.

• no pudo confirmar = she couldn’t confirm it (on that particular occasion)
• no podía confirmar = she wasn’t able to / couldn’t, often suggesting an ongoing inability or a more general situation

Because the sentence refers to a specific event connected to la reunión de ayer, the preterite pudo fits well.

Compare:

• Ayer no pudo venir. = Yesterday she couldn’t come.
• Cuando estaba enferma, no podía trabajar. = When she was ill, she couldn’t work.

Confirmar su asistencia means to confirm her attendance or to confirm that she would attend.

Breakdown:

• confirmar = to confirm
• su = her / his / your / their, depending on context
• asistencia = attendance / presence

This is a common formal expression, especially for meetings, events, invitations, or appointments.

Examples:

• Debes confirmar tu asistencia. = You must confirm your attendance.
• No confirmó su asistencia al evento. = She didn’t confirm her attendance at the event.

Yes. Su can mean his, her, your (formal), their, depending on context.

In this sentence, because the implied person is female (enferma), su asistencia is understood as her attendance.

Spanish uses su much more broadly than English uses her. If the writer wanted to make it absolutely explicit, they could say something like:

• la asistencia de ella

But that usually sounds less natural unless there is a need to clarify or contrast.

Because the noun asistencia commonly takes the preposition a to mean attendance at something.

So:

• asistencia a la reunión = attendance at the meeting

This is similar to:

• asistencia al evento = attendance at the event
• asistencia a clase = attendance in class / going to class

Using de would not work here with this meaning.

De ayer means from yesterday or, more naturally in English, yesterday’s.

So:

• la reunión de ayer = yesterday’s meeting / the meeting from yesterday

Spanish often uses de + time expression where English might use a possessive-style structure.

Examples:

• el partido de ayer = yesterday’s match
• la clase de hoy = today’s class
• la noticia de esta mañana = this morning’s news

Yes. Spanish allows some flexibility, though some versions sound more natural than others.

Original:

• Como estaba enferma, no pudo confirmar su asistencia a la reunión de ayer.

You could also say:

• No pudo confirmar su asistencia a la reunión de ayer porque estaba enferma.

This means the same thing, but the structure changes:

• como puts the reason first
• porque gives the reason after the main statement

Both are natural. The original sentence sounds slightly more formal or written.

It is neutral to fairly formal. The phrase confirmar su asistencia is especially common in formal or semi-formal contexts such as meetings, work events, invitations, and appointments.

A more everyday version might be:

• Como estaba enferma, no pudo decir si iba a ir a la reunión de ayer.

But the original sentence is perfectly natural, especially in work or administrative contexts.

Usually, no. This is a very important false friend.

In Spanish:

• asistencia often means attendance
• it can also mean help/support in some contexts, but not usually in the same everyday sense as English assistance

In this sentence, su asistencia definitely means her attendance, not her help.

If you want assistance/help, Spanish often uses:

• ayuda = help
• asistencia in certain formal contexts, like technical support or medical care

So be careful: confirmar su asistencia does not mean confirm her assistance.

Only the adjective would need to change:

• Como estaba enfermo, no pudo confirmar su asistencia a la reunión de ayer.

That means:

• Since he was ill, he couldn’t confirm his attendance at yesterday’s meeting.

Everything else can stay the same because:

• estaba works for both he and she
• pudo works for both he and she
• su can mean his or her

The adjective enfermo/enferma is what makes the gender clear here.