El rímel resistente al agua no sale bien sin desmaquillante.

In standard Spanish, rímel is usually treated as a masculine noun, so el rímel is the normal form.

A learner should also know:

• In Spain, rímel is very common.
• Another very common way to say it is la máscara de pestañas.

So you may hear both:

• el rímel
• la máscara de pestañas

They both refer to mascara, but the grammar changes because the nouns have different genders.

The accent mark in rímel shows where the stress goes: RÍ-mel.

Without the accent, a Spanish reader would expect a different stress pattern. Spanish spelling uses accent marks to make pronunciation clear, so rímel keeps the written stress on the first syllable.

Literally, resistente al agua means resistant to water.

In natural English, that usually corresponds to:

• water-resistant
• waterproof (depending on context)

With mascara, resistente al agua is the normal Spanish way to describe something that does not wash off easily with water.

Al is the contraction of a + el.

So:

• a + el = al

Here, resistente is followed by the preposition a:

• resistente a algo = resistant to something

Then we get:

• resistente a el agua → resistente al agua

So al is required.

Yes, agua is a feminine noun.

However, singular feminine nouns that begin with a stressed a- sound often use el instead of la for pronunciation reasons:

• el agua
• el águila
• el alma

But they are still feminine. You can see that in adjectives:

• el agua fría
• not el agua frío

So in al agua, the el does not mean the noun is masculine.

In Spanish, descriptive information often comes after the noun.

So:

• el rímel resistente al agua

is the normal word order for:

• the water-resistant mascara

The phrase resistente al agua works like a description attached to rímel.

That is one of the most important points in this sentence.

Here, salir is being used in an extended sense. With things like:

• stains
• dirt
• paint
• makeup

salir can mean:

• to come off
• to wash out
• to be removed

So no sale bien means something like:

• it doesn’t come off well
• it doesn’t come off easily

This is a very natural use in Spanish.

Because the subject is el rímel, which is singular.

So the verb must also be singular:

• el rímel ... sale

If the subject were plural, the verb would change:

• Los rímeles resistentes al agua no salen bien sin desmaquillante.

Bien softens and specifies the idea.

Compare:

• no sale = it doesn’t come off
• no sale bien = it doesn’t come off well / properly / easily

So bien suggests that removal is possible, but not effective or not easy without makeup remover.

It makes the sentence sound more natural than a flat no sale.

Because sin + noun often appears without an article when speaking in a general sense.

So:

• sin desmaquillante = without makeup remover

This means without using makeup remover in general, not without one specific remover.

If you say:

• sin un desmaquillante

it sounds more like without a particular makeup remover or without any makeup-removing product in a more concrete sense.

The version in the sentence is the most natural general phrasing.

Here, desmaquillante is a noun meaning makeup remover.

But it can also be an adjective in other contexts, for example:

• loción desmaquillante
• leche desmaquillante

So the word itself can function in more than one way, but in this sentence it clearly means the product: makeup remover.

Yes, absolutely.

You could say:

• El rímel resistente al agua no se quita bien sin desmaquillante.

That also means:

• Waterproof mascara doesn’t come off well without makeup remover.

The difference is mainly one of perspective:

• no sale bien focuses on the mascara coming off
• no se quita bien focuses on the act of removing it

Both are natural, but no sale bien is very idiomatic in Spanish.

Spanish often uses the definite article to talk about things in a general sense.

So:

• El rímel resistente al agua no sale bien sin desmaquillante

can mean mascara of that type in general, not just one specific tube.

This is very common in Spanish:

• El café me gusta.
• La leche es buena para...
• El tabaco es malo para la salud.

English often drops the article in these cases, but Spanish usually keeps it.