Se arriva mia zia, metterò il copriletto bianco anche nella stanza degli ospiti.

In Italian, after se meaning if, you normally use the present tense when you are talking about a real possible future situation:

• Se arriva mia zia, ...
• If my aunt arrives, ...

Even though English often uses present here too (if she arrives), English speakers sometimes expect a future form because the result clause is in the future. Italian does not normally say se arriverà in this kind of sentence.

So the pattern is:

• se + present
• future in the main clause

Example:

• Se piove, resteremo a casa.
• If it rains, we’ll stay home.

Metterò is the 1st person singular future simple of mettere:

• io metterò = I will put / I’ll put

The speaker is talking about something they will do later, if the condition happens. That is why the main clause uses the future:

• Se arriva mia zia, metterò...
• If my aunt arrives, I’ll put...

This is a very common structure in Italian:

• Se + present, future
• If + present, will + verb

With singular family members, Italian usually leaves out the article when using a possessive adjective:

• mia zia = my aunt
• mio fratello = my brother
• nostra madre = our mother

So mia zia is the normal form here.

However, the article is used in some cases, for example:

1. Plural family members

   • le mie zie = my aunts

2. When the family noun is modified

   • la mia cara zia = my dear aunt

3. Sometimes with certain forms like loro

So in this sentence, mia zia is correct because it is a singular close family member with no modifier.

Italian often allows the subject to come after the verb, especially when introducing a person or event, or when the verb comes first naturally in the sentence.

So:

• arriva mia zia literally looks like
• arrives my aunt

But it simply means:

• my aunt arrives / if my aunt arrives

This word order is completely natural in Italian. You could also say:

• Se mia zia arriva, ...

That is also correct, but Se arriva mia zia sounds very natural and can slightly emphasize the arrival itself.

Mettere is a very common verb meaning to put, to place, or sometimes to put on / lay out / set up, depending on context.

In this sentence, metterò il copriletto bianco means something like:

• I’ll put the white bedspread on
• I’ll lay out the white bedspread
• I’ll use the white bedspread

So it is not just a literal put in the abstract; it refers to arranging the bed with that bedspread.

Copriletto means bedspread or bed cover.

It is different from some other bedding words:

• copriletto = bedspread
• coperta = blanket
• lenzuolo = sheet
• piumone = duvet

So il copriletto bianco is the white bedspread.

In Italian, adjectives usually come after the noun:

• il copriletto bianco
• the white bedspread

This is the normal order.

Sometimes adjectives can come before the noun, but that often changes the tone, emphasis, or style. For a basic descriptive adjective like color, the most natural position is after the noun:

• una casa grande
• un vestito rosso
• il copriletto bianco

Also, bianco agrees with copriletto, which is masculine singular, so the form is bianco.

Nella is a contraction of:

• in + la = nella

So:

• nella stanza = in the room

Italian very often combines prepositions with definite articles:

• in + il = nel
• in + lo = nello
• in + la = nella
• in + i = nei
• in + gli = negli
• in + le = nelle

Here, stanza is feminine singular, so it takes la, giving nella stanza.

Degli is a contraction of:

• di + gli = degli

So:

• la stanza degli ospiti literally = the room of the guests

In natural English, that becomes:

• the guest room

This is a very common Italian structure:

• il libro degli studenti = the students’ book / the book of the students
• la camera dei bambini = the children’s room

Here, ospiti is plural, so Italian uses the plural article gli, which combines with di to make degli.

Italian often uses a structure like room of the guests where English prefers a noun used adjectivally, like guest room.

So:

• stanza degli ospiti literally = room of the guests
• natural English = guest room

The plural ospiti does not mean a specific number of guests in this sentence. It just refers to the room intended for guests in general.

Also, ospite is a noun whose singular form can refer to either masculine or feminine, and the plural is ospiti.

Anche means also / too.

In this sentence:

• anche nella stanza degli ospiti

it means something like:

• also in the guest room
• in the guest room too

So the idea is that the speaker will put the white bedspread there as well, not only somewhere else.

Its position is important. Here it is closely linked to the place phrase:

• also in the guest room

Yes. Italian is more flexible than English with word order.

For example, you could also hear:

• Se mia zia arriva, metterò il copriletto bianco anche nella stanza degli ospiti.

This has the same basic meaning.

You might also move anche depending on emphasis, though not every position sounds equally natural. The original version is very natural and clear.

Italian word order often changes to highlight different parts of the sentence, while English is usually more fixed.

Italian often leaves out subject pronouns when they are not needed, because the verb ending already shows who the subject is.

• metterò already means I will put
• so io is optional

That is why Italian usually says:

• metterò

rather than:

• io metterò

You add io only for emphasis, contrast, or clarity, for example:

• Io metterò il copriletto, non tu.
• I’ll put the bedspread on, not you.