El pomelo me parece más amargo que la naranja.

Me parece means it seems to me or it strikes me. The me shows whose impression it is.

So:

• El pomelo parece más amargo... = The grapefruit seems more bitter...
• El pomelo me parece más amargo... = The grapefruit seems more bitter to me / in my opinion

In this sentence, me adds a personal point of view.

Here, parece comes from parecer, which often means to seem or to appear.

So El pomelo me parece más amargo que la naranja is literally something like:

The grapefruit seems more bitter to me than the orange.

It is not saying an absolute scientific fact; it is giving an impression or opinion.

Yes. Pomelo is a masculine noun in Spanish, so it takes el:

• el pomelo

In Spanish, noun gender is grammatical, so you usually just have to learn it with the noun.

A useful habit is to learn new nouns together with their article:

• el pomelo
• la naranja

The adjective must agree with the noun it describes.

Here, amargo describes el pomelo, which is masculine singular, so the adjective is also masculine singular:

• el pomelo amargo

If you were describing la naranja, you would say:

• la naranja amarga

In this sentence, the comparison is about the grapefruit, so amargo is correct.

Más ... que is the standard way to make comparisons of inequality in Spanish, just like more ... than in English.

So:

• más amargo que = more bitter than

This pattern is very common:

• más grande que = bigger than
• más caro que = more expensive than
• más rápido que = faster than

Because after a comparative like más, Spanish normally uses que to mean than:

• más amargo que la naranja = more bitter than the orange

De is used in other structures, but not in this basic comparison pattern.

So remember:

• más ... que = more ... than
• menos ... que = less ... than
• tan ... como = as ... as

Spanish often uses the definite article with nouns in a general sense, more often than English does.

So la naranja here can refer to the orange as a type of fruit, not necessarily one specific orange on the table.

This is very natural in Spanish. Compare:

• Me gusta el café = I like coffee
• La naranja es dulce = Oranges are sweet / The orange is sweet as a fruit

So que la naranja sounds normal and idiomatic.

It can often be understood as a general comparison between the two fruits as types, especially without extra context.

So it may mean something like:

• Grapefruit seems more bitter to me than orange

But context could also make it specific, for example if two fruits are being tasted right now.

Spanish allows this kind of ambiguity, just as English sometimes does.

Yes. That sentence is correct.

The difference is:

• El pomelo parece más amargo que la naranja = a more neutral observation, the grapefruit seems more bitter than the orange
• El pomelo me parece más amargo que la naranja = explicitly to me, giving your personal impression

So both work, but me makes the opinion more personal.

Yes, and it is very natural. It means:

• I think grapefruit is more bitter than orange

The nuance is slightly different:

• me parece = it seems to me
• creo que = I think that

Me parece can sound a bit softer or more based on impression.
Creo que can sound a bit more direct as an opinion.

Yes, Spanish word order is flexible, and different orders are possible.

The most neutral order here is:

• El pomelo me parece más amargo que la naranja

If you say:

• Me parece más amargo el pomelo que la naranja

it is still understandable, but it sounds more marked or less neutral. Learners should usually stick with the original order unless they have a reason to emphasize something.

Yes. In Spain, pomelo is the normal word for grapefruit.

In some parts of Latin America, you may also hear toronja.

So for Spanish from Spain, pomelo is the expected choice.

In this sentence, yes, because it refers to el pomelo, which is masculine singular.

But the structure changes with gender and number:

• el pomelo es más amargo
• la naranja es más amarga
• los pomelos son más amargos
• las naranjas son más amargas

The más part does not change, but the adjective does.

Yes, very often.

A common pattern is:

• algo + parecer + adjective
• algo + me/te/le... + parecer + adjective

Examples:

• La sopa parece fría = The soup seems cold
• La película me parece interesante = The film seems interesting to me
• El pomelo me parece más amargo que la naranja

So this sentence uses a very common and useful structure.