Si esa no me queda bien, me probaré la otra.

Because Spanish often leaves out the noun when it is already understood from the context.

Here, esa means that one and la otra means the other one. The missing noun is feminine singular, probably something like camisa, chaqueta, falda, etc.

So the full idea is something like:

• Si esa camisa no me queda bien, me probaré la otra camisa.

But Spanish normally avoids repeating the noun if it is obvious.

They are feminine because they refer to a feminine noun that is being left out.

For example:

• esa falda / la otra
• esa chaqueta / la otra

If the item were masculine, you would get:

• Si ese no me queda bien, me probaré el otro.

And if it were plural:

• Si esas no me quedan bien, me probaré las otras.

Here quedar bien means something like to fit me well or to suit me.

So:

• esa no me queda bien = that one doesn’t fit me well / doesn’t look right on me

With clothes, quedar bien can refer to:

• the size or fit
• how flattering it looks
• both at once

So it is broader than just fit in a strictly physical sense.

That me shows the person affected: on me / to me.

So:

• me queda bien = it fits me well / it looks good on me
• te queda bien = it fits you well
• le queda bien = it fits him/her well

This is very common with quedar when talking about clothes.

That me is part of the verb probarse, which means to try on.

So:

• probar = to try, test, taste
• probarse = to try on oneself, especially clothes

Therefore:

• me probaré la otra = I’ll try on the other one

In Spain, probarse is especially common for clothing.

Yes, you may hear it, and people would probably understand you from the context. But with clothes, me probaré la otra is clearer and more natural because it explicitly means I’ll try the other one on.

Without me, probar can mean more general things like:

• try
• test
• taste

So for clothes, probarse is the safer and more idiomatic choice.

Because this is a normal if sentence about a real possibility.

Structure:

• Si + present indicative, then
• future (or another main-clause tense)

So:

• Si esa no me queda bien, me probaré la otra. = If that one doesn’t fit me well, I’ll try on the other one.

Spanish does not use the conditional after this kind of si.

So Si esa no me queda bien, me probaría la otra would not be the standard choice here.

Because Spanish uses the present indicative after si when talking about a real or likely condition in the present or future.

This is the normal pattern:

• Si tengo tiempo, iré.
• Si me queda bien, me la llevo.
• Si esa no me queda bien, me probaré la otra.

English often uses present + future too:

• If it doesn’t fit, I’ll try the other one.

So this matches English fairly well.

Because la otra means the other one, referring to a specific alternative that both speaker and listener know about.

Compare:

• otra = another one
• la otra = the other one

So here the speaker is choosing between known options, probably two garments:

• If that one doesn’t fit me well, I’ll try on the other one.

Using la makes it definite.

Because the subject is singular: esa.

Even though the noun is omitted, it is still understood as one feminine singular item.

So:

• esa ... queda
• esas ... quedan

Examples:

• Si esa no me queda bien...
• Si esas no me quedan bien...

The verb agrees with the thing being talked about, not with me.

They are demonstratives:

• esta = this one
• esa = that one
• aquella = that one over there / that one further away

In Spain, this three-way distinction is still commonly taught and often used.

In this sentence, esa suggests that one rather than this one. It may be physically farther away, or simply one of the available options that the speaker is pointing out.

It can mean both.

With clothes, me queda bien can mean:

• it fits me well
• it looks good on me
• it suits me

So the sentence may be about size, style, or overall fit/appearance.

If you want to be more specifically about size, Spanish might use other expressions too, depending on context, such as:

• me viene bien
• me está bien
• no me entra
• me queda grande / pequeño

But me queda bien is very natural and common.

Here si and no are two separate words:

• si = if
• no = not

So:

• Si esa no me queda bien... = If that one doesn’t fit me well...

This is different from sino, which is a different word meaning but rather / except in certain contexts.

So here it must be si no, not sino.

Yes, to some extent. The given sentence is very natural:

• Si esa no me queda bien, me probaré la otra.

You could also hear small variations, for example:

• Si esa no me queda bien, probaré la otra.
• Si no me queda bien esa, me probaré la otra.

But the original version sounds very standard and clear.

The pronoun me normally goes before a conjugated verb:

• me queda
• me probaré

So you would not say probaréme in modern Spanish.