A criança entrou sem chorar, mas saiu com um sorriso enorme e sem nenhuma lágrima.

Because criança is a feminine noun in Portuguese, so it takes a.

A very important detail: criança means child, and it can refer to a boy or a girl, but the word itself is grammatically feminine. So you say:

• a criança pequena
• a criança entrou
• a criança estava feliz

This does not necessarily mean the child is female. It just means the noun criança is feminine.

Both entrou and saiu are in the preterite tense, which is commonly used in Brazilian Portuguese for completed actions in the past.

• entrou = entered / went in
• saiu = left / went out / came out

In this sentence, the child did two clearly completed actions:

1. entered
2. left

So the preterite is the natural choice.

If you used the imperfect instead, it would suggest an ongoing or habitual situation, which would not fit as well here.

After sem (without), Portuguese often uses the infinitive to express without doing something.

So:

• sem chorar = without crying
• sem falar = without speaking
• sem olhar = without looking

This is very normal in Portuguese. English uses without + -ing, but Portuguese usually uses sem + infinitive.

So even though English says without crying, Portuguese says literally without to cry.

Yes, but it would mean something slightly different and sound more specific.

• sem chorar = without crying
• sem estar chorando = without being crying / without being in the middle of crying

In most normal situations, sem chorar is the most natural and simple option.
Sem estar chorando is more emphatic or descriptive and usually unnecessary here.

Because mas means but, and it connects two contrasting parts of the sentence.

• A criança entrou sem chorar
• mas saiu com um sorriso enorme e sem nenhuma lágrima

The comma helps separate those two contrasting ideas, just like in English:

• The child went in without crying, but came out with a huge smile...

In Portuguese, it is standard to use a comma before mas in this kind of structure.

Portuguese often uses an article in places where English might omit one.

• com um sorriso enorme = with a huge smile

Using um makes the phrase sound natural and complete.
Without um, com sorriso enorme would sound odd or incomplete in most contexts.

This is similar to how Portuguese often says:

• ela tem um carro
• ele deu um grito
• saiu com um sorriso

Even if English sometimes sounds fine without an article, Portuguese usually wants one here.

In Portuguese, adjectives usually come after the noun.

So:

• um sorriso enorme = a huge smile
• uma casa bonita = a beautiful house
• um problema sério = a serious problem

Sometimes adjectives can come before the noun, but that often changes the tone, emphasis, or style.
Here, um enorme sorriso is also possible, but it sounds a bit more literary or emphatic.

The most neutral and common form is:

• um sorriso enorme

Both are possible, but they have slightly different effects.

• sem lágrimas = without tears
• sem nenhuma lágrima = without any tears / without a single tear

Using nenhuma adds emphasis. It makes the idea stronger and clearer: not even one tear.

So the sentence gives a stronger emotional contrast:

• entered without crying
• left with a huge smile
• and with absolutely no tears

Because in Portuguese, nenhum/nenhuma is very often used with a singular noun:

• nenhuma lágrima = no tear / not a single tear
• nenhum problema = no problem
• nenhuma dúvida = no doubt

Even though English may use a plural in similar cases, Portuguese commonly uses the singular after nenhum/nenhuma.

You can find plural forms like nenhumas lágrimas, but they are much less common and often sound marked or unusual.
The normal phrasing here is:

• sem nenhuma lágrima

Because the sentence is built around a contrast.

• entrou sem chorar = entered without crying
• saiu com um sorriso enorme = left with a huge smile
• e sem nenhuma lágrima = and without any tears

The writer is showing a change in the child’s emotional state.
Using sem and com helps paint that contrast very clearly:

• no crying
• big smile
• no tears

This kind of structure is very natural in Portuguese.

It can be understood as either, depending on context.

• sair basically means to leave / to go out / to come out

So:

• saiu can be left
• or came out

In this sentence, English might naturally say:

• The child went in without crying, but came out with a huge smile...

That sounds especially natural if we imagine the child entering a room, doctor’s office, school, etc.

So saiu is flexible, and the best English translation depends on the situation.

They are related, but they are different kinds of words.

• chorar = to cry — a verb
• lágrima = tear — a noun

So:

• sem chorar = without crying
• sem nenhuma lágrima = without any tear / without a single tear

Using both in the same sentence is not redundant. It adds nuance:

• not crying
• not even showing tears

That makes the final image more vivid.

Yes, it sounds natural and expressive.

It has a nice contrast and a smooth rhythm:

• A criança entrou sem chorar
• mas saiu com um sorriso enorme
• e sem nenhuma lágrima

It sounds like something you might read in a story, hear in conversation, or see in a description of a child’s experience.

A slightly simpler version could be:

• A criança entrou sem chorar, mas saiu sorrindo e sem nenhuma lágrima.

But the original sentence is absolutely natural and well-formed.