Dudé entre un cucurucho grande y una tarrina pequeña, pero acabé por elegir el helado en cucurucho.

Here dudé is better understood as I hesitated or I was undecided, not I doubted in the English sense of not believing something.

In Spanish, dudar can mean:

• to doubt: Dudo que sea verdad = I doubt it’s true
• to hesitate / be unsure: Dudé entre dos opciones = I hesitated between two options

So in this sentence, Dudé entre... means the speaker was wavering between two choices.

Dudar entre X y Y means to hesitate between X and Y.

Pattern:

• dudar entre + option 1 + y + option 2

Example:

• Dudé entre un café y un té = I hesitated between a coffee and a tea

This is different from other uses of dudar, such as:

• dudar de algo = to doubt something
• dudar si... = to be unsure whether...

So Dudé entre un cucurucho grande y una tarrina pequeña is a very natural way to say the speaker couldn’t decide between those two options.

After entre, Spanish normally uses y to link the two options.

So:

• entre A y B = between A and B

Not:

• entre A o B

This is one of those fixed patterns that learners just have to get used to. Even though English often uses or when talking about choices, Spanish says entre... y... after entre.

In Spain, cucurucho usually means an ice-cream cone.

So:

• un cucurucho grande = a large cone

A native English speaker might expect cono, and that word does exist, but in Spain cucurucho is very common for the cone you get ice cream in, especially in everyday speech or at an ice-cream shop.

Depending on context, cucurucho can also refer more generally to something cone-shaped, but here it clearly means an ice-cream cone.

A tarrina is the small tub, cup, or container that ice cream is served in.

In Spain, if you buy ice cream and don’t want it in a cone, you often get it en tarrina.

So:

• una tarrina pequeña = a small tub/cup

This is a very Spain-specific everyday word in the context of ice cream. In other Spanish-speaking places, other words may be more common.

In Spanish, descriptive adjectives usually come after the noun.

So:

• un cucurucho grande
• una tarrina pequeña

That is the normal order for describing size, color, shape, etc.

Also notice agreement:

• cucurucho is masculine singular, so grande stays singular and works for masculine/feminine
• tarrina is feminine singular, so pequeña is feminine singular

So the adjective position and agreement are both completely regular here.

They are in the preterite because the sentence describes a completed sequence of events in the past:

1. the speaker hesitated
2. then the speaker ended up choosing

So:

• dudé = I hesitated
• acabé = I ended up

The preterite fits well because these are seen as finished actions in a story. If you used the imperfect, it would suggest background, repetition, or an ongoing state instead.

Acabar por + infinitive means to end up doing something or to eventually do something.

So:

• acabé por elegir = I ended up choosing / I eventually chose

The por is part of this expression. It adds the idea that after some process, hesitation, or development, that was the final result.

Very similar alternatives are:

• acabé eligiendo = I ended up choosing
• al final elegí = in the end I chose

All are natural, but acabé por elegir slightly highlights the process that led to the final decision.

El helado en cucurucho means the ice cream in a cone or more naturally the ice cream served in a cone.

The speaker could have said simply:

• acabé por elegir el cucurucho

But el helado en cucurucho is more explicit. It makes clear that the choice is about the form in which the ice cream is served.

So en cucurucho describes helado, not the verb elegir. It is not saying the speaker chose something while physically being in a cone; it means the chosen serving format was a cone.

In this kind of expression, Spanish often leaves out the article when talking about the type of serving format or presentation.

So these are natural:

• helado en cucurucho
• helado en tarrina

This is similar to saying by cone / in cone form rather than referring to one specific cone as an object.

If you say en un cucurucho, that sounds more like you are thinking of an actual individual cone. That can also be correct in some contexts, but here en cucurucho is the more idiomatic way to describe how the ice cream is served.

Using el helado here makes the choice sound more definite and specific: the speaker is referring back to the ice cream they were deciding about.

It is a bit like saying:

• I hesitated between these two options, but in the end I chose the ice cream in a cone

Spanish often uses the definite article when the thing is already understood from context.

You might also hear:

• acabé por elegir un helado en cucurucho

That would also be grammatical, but it can sound a little more like introducing the item for the first time. In this sentence, el helado fits the idea that the choice is now settled and identifiable.

Yes. The original sentence is perfectly correct, but some speakers might choose a slightly simpler or more everyday version, such as:

• Dudé entre un cucurucho grande y una tarrina pequeña, pero al final elegí el cucurucho.
• Dudé entre un cucurucho grande y una tarrina pequeña, pero acabé eligiendo el helado en cucurucho.
• Dudé entre un cucurucho grande y una tarrina pequeña, pero al final me decidí por el cucurucho.

These all keep the same basic meaning. The original version is natural, but acabé por elegir is a bit more formal or literary than the simplest everyday option.