Mi jefa va a proponer un horario más flexible.

Jefa is the feminine form of jefe and means female boss or female manager.

• mi jefe = my male boss
• mi jefa = my female boss

Because the sentence is referring to a woman, jefa is used.

Va a proponer is the very common Spanish structure ir a + infinitive, which means to be going to + verb.

So:

• va a proponer = is going to propose / is going to suggest

In this kind of workplace context, proponer often sounds more like suggest or put forward than a very formal English propose.

Because the subject is mi jefa, which is third person singular.

The verb ir changes depending on the subject:

• yo voy
• tú vas
• él/ella va
• nosotros/nosotras vamos
• ellos/ellas van

Since mi jefa = she, the correct form is va.

Yes, mi here means my.

It does not have an accent because it is the possessive adjective:

• mi jefa = my boss

With an accent, mí means me after a preposition:

• para mí = for me
• sin mí = without me

So:

• mi = my
• mí = me

Proponer means to propose, to suggest, or to put forward.

In English, propose can sound quite formal, but Spanish proponer is often used in everyday situations too. In this sentence, it most naturally means something like:

• my boss is going to suggest
• my boss is going to put forward

It does not automatically imply something very formal.

Horario can mean several related things depending on context:

• schedule
• timetable
• working hours
• work schedule

In this sentence, un horario más flexible most likely means a more flexible work schedule or more flexible working hours.

Un is the indefinite article: a/an.
El is the definite article: the.

So:

• un horario = a schedule
• el horario = the schedule

Here, un horario más flexible suggests that the boss is going to propose some kind of more flexible schedule, not necessarily a specific one already identified.

In Spanish, adjectives often come after the noun.

So:

• un horario flexible = a flexible schedule
• un horario más flexible = a more flexible schedule

This is the normal word order in Spanish. English usually puts adjectives before the noun, but Spanish commonly puts them after.

Because the sentence gives a comparative idea without explicitly stating the second part.

• más flexible = more flexible

You only need que when you say what it is being compared with:

• un horario más flexible que el actual = a schedule more flexible than the current one

Without that second part, más flexible still works perfectly and simply means more flexible.

No. Flexible stays the same in the singular for both masculine and feminine nouns.

• un horario flexible
• una política flexible

In the plural, it becomes:

• horarios flexibles
• políticas flexibles

So in this sentence, flexible does not change because horario is singular.

Yes. You could say:

• Mi jefa propondrá un horario más flexible.

That also means My boss will propose a more flexible schedule.

However, ir a + infinitive (va a proponer) is extremely common in everyday spoken Spanish and often sounds more natural in conversation, especially when talking about a near or expected future.

Because un horario is a thing, not a person.

The personal a is usually used before a specific person as a direct object:

• Veo a mi jefa. = I see my boss.

But with things, you normally do not use it:

• Mi jefa va a proponer un horario.

So there is no a before un horario.

Yes, jefa is completely natural in Spain for female boss.

Depending on the exact workplace, other words might also be used, such as:

• directora
• encargada
• supervisora
• responsable

But mi jefa is a very normal, everyday way to say my boss if your boss is a woman.

The sentence follows a very common Spanish pattern:

Mi jefa + va a proponer + un horario más flexible

So:

• Mi jefa = subject
• va a proponer = verb phrase
• un horario más flexible = direct object

A helpful literal breakdown is:

• Mi jefa = My boss
• va a = is going to
• proponer = propose / suggest
• un horario más flexible = a more flexible schedule

That makes it a very useful model sentence for building similar ones.