Sin desmaquillante, no me quito bien el rímel.

After sin, Spanish often uses a bare noun when speaking generally.

• sin desmaquillante = without makeup remover, in general
• sin el desmaquillante = without the makeup remover, a specific one already known from the context

So in this sentence, sin desmaquillante sounds natural because it means without using makeup remover at all.

Because quitarse is very common when someone removes something from their own body/face/hair.

Here, me shows that the action affects the speaker themself:

• me quito el rímel = I remove the mascara from myself
• quito el rímel = I remove the mascara

The second version is grammatically possible, but it sounds less natural here because it does not clearly express that the speaker is taking it off their own eyes/face.

With a conjugated verb, object/reflexive pronouns normally go before the verb in Spanish:

• no me quito
• me lavo
• te pones

That is why you get no me quito bien el rímel.

If the verb were in the infinitive, the pronoun could attach to the end:

• quitarme el rímel
• No puedo quitarme bien el rímel

So me quito is just the normal placement with a finite verb.

Spanish often uses the definite article instead of a possessive when it is already obvious whose thing it is, especially with things on the body or closely connected to the person.

So:

• me quito el rímel sounds natural
• me quito mi rímel is possible, but it adds emphasis, contrast, or sounds less neutral

Using el does not mean someone else’s mascara. It just means the mascara the speaker is wearing.

Because bien is modifying the verb phrase me quito.

Spanish often places adverbs like bien, mal, fácilmente, rápidamente near the verb:

• no me quito bien el rímel

This is the most natural word order here.

You may also hear:

• no me quito el rímel bien

but that version usually sounds a bit less neutral or shifts the rhythm/emphasis. The original sentence is the more standard phrasing.

Quito is the 1st person singular present indicative of quitar.

In this sentence, the present is not necessarily about right now at this exact moment. It can express a general fact, habit, or repeated experience:

• whenever I try, this is what happens
• in general, without makeup remover, I do not remove my mascara properly

Spanish uses the present this way very often.

Yes, rímel is very common in Spain.

Another common term is:

• máscara de pestañas

Nuance:

• rímel sounds very everyday and common in Spain
• máscara de pestañas is also correct and may sound a bit more explicit or neutral

The accent mark in rímel shows the stress is on the first syllable: RÍ-mel. Without the accent, Spanish spelling rules would suggest a different stress pattern.

Sometimes, yes, but the meaning shifts a bit.

• desmaquillarme = to remove my makeup
• quitarme el rímel = to remove my mascara specifically

So:

• Sin desmaquillante, no me desmaquillo bien
  = I do not remove my makeup well without makeup remover

That is broader.

If you want to focus specifically on mascara, quitarme el rímel is more precise.

Yes, a little.

• no me quito bien el rímel = I do not remove my mascara properly / I do not get it off well
• no puedo quitarme bien el rímel = I cannot remove my mascara properly

Adding puedo makes the idea of inability more explicit. The original sentence sounds a bit more natural and conversational because Spanish often states the result directly without needing can/cannot.

This is a very useful distinction.

• no me quito bien el rímel = I do not remove the mascara well
  The speaker is presented as the active doer of the action.

• no se me quita bien el rímel = the mascara does not come off well for me
  This focuses more on the mascara being difficult to remove, rather than on the speaker’s action.

So the second version sounds a bit more like:

• it is stubborn
• it does not come off easily

Both are natural, but they highlight different things.