En lo que respecta a los honorarios, los confirmamos.

It is a formal linking expression meaning as for, regarding, or with regard to.

So:

En lo que respecta a los honorarios
= As regards the fees / With regard to the fees

It is common in formal writing, business emails, legal language, and official communication.

Yes. It sounds quite formal and polished.

In less formal Spanish, you are more likely to hear:

• Sobre los honorarios...
• Respecto a los honorarios...
• En cuanto a los honorarios...

All of these can mean roughly the same thing, but En lo que respecta a is one of the more formal options.

Because lo que is a neuter structure in Spanish. It does not refer to a masculine or feminine noun directly. Instead, it means something like that which or what in an abstract sense.

In En lo que respecta a..., the phrase works as a fixed expression:

• lo que respecta a = what concerns / what relates to

So you should think of en lo que respecta a as a set phrase, not as something that agrees with honorarios.

Honorarios usually means fees, especially professional fees.

It is commonly used for money paid to professionals such as:

• lawyers
• consultants
• architects
• translators
• doctors

It is more specific and formal than general words like:

• precios = prices
• tarifas = rates / charges
• salario / sueldo = salary / wages

So honorarios is the right word when talking about payment for professional services.

Because in Spanish, professional fees are very often expressed in the plural: los honorarios.

This is similar to English, where fees is also often plural. Even if you are talking about one overall amount, Spanish commonly uses the plural form.

So:

• los honorarios = the fees
• less commonly in this context, el honorario = the fee

In business Spanish, the plural is very normal.

The comma separates the introductory topic phrase from the main clause.

• En lo que respecta a los honorarios, = topic-setting phrase
• los confirmamos. = main statement

This is similar to English punctuation in a sentence like:

• As for the fees, we confirm them.

The comma helps make the structure clear and sounds natural in writing.

Because los is a direct object pronoun replacing los honorarios.

So the sentence is structured like this:

• los honorarios = the fees
• los confirmamos = we confirm them

Spanish often avoids repeating the noun and uses a pronoun instead.

So instead of saying:

• En lo que respecta a los honorarios, confirmamos los honorarios.

which sounds repetitive, Spanish says:

• En lo que respecta a los honorarios, los confirmamos.

In Spanish, object pronouns usually go before a conjugated verb.

So:

• los confirmamos = we confirm them

This is the normal word order with a finite verb.

Compare:

• Lo veo = I see it
• La tenemos = we have it
• Los confirmamos = we confirm them

Pronouns are attached to the end only in certain cases, such as with infinitives, gerunds, and affirmative commands:

• confirmarlos
• estamos confirmándolos
• confírmalos

But with confirmamos, they go before the verb.

Grammatically, confirmamos can be either:

• present indicative: we confirm
• preterite: we confirmed

The forms are identical.

In this sentence, the most likely reading is present:

• As regards the fees, we confirm them.

That is especially likely in business or formal correspondence.

Only the wider context tells you for certain which tense is meant.

Because Spanish usually omits subject pronouns when the verb ending already makes the subject clear.

• confirmamos already tells you the subject is we

So:

• los confirmamos = we confirm them

Adding nosotros is possible, but it is usually unnecessary unless you want emphasis or contrast:

• Nosotros los confirmamos, pero ellos no.
  = We confirm them, but they do not.

In a neutral sentence, leaving out nosotros is more natural.

Yes, in formal or business language it can sound natural. It usually implies something like:

• we confirm the agreed fees
• we confirm that those fees are accepted
• we confirm the fee arrangement

In practice, this kind of wording often appears in professional emails, contracts, or administrative communication.

Depending on context, other verbs could also appear, such as:

• aceptamos los honorarios = we accept the fees
• aprobamos los honorarios = we approve the fees
• ratificamos los honorarios = we ratify the fees

But confirmamos is perfectly plausible in formal correspondence.

Yes. Some common alternatives are:

• Respecto a los honorarios, los confirmamos.
• En cuanto a los honorarios, los confirmamos.
• Sobre los honorarios, los confirmamos.

These all mean roughly the same thing, but there are slight differences in tone:

• En lo que respecta a = quite formal
• Respecto a = formal but common
• En cuanto a = very common, neutral
• Sobre = simpler, often a bit more direct

For everyday formal Spanish, En cuanto a or Respecto a are often the easiest alternatives.

Not very often. It sounds more like written formal Spanish than casual speech.

In conversation, a speaker would probably say something simpler, such as:

• Sobre los honorarios, los confirmamos.
• En cuanto a los honorarios, sí, los confirmamos.
• Los honorarios quedan confirmados.

So the original sentence is natural, but mainly in professional, administrative, or formal contexts.