La salsa de tomate está buena con albahaca fresca.

Because salsa is a feminine singular noun in Spanish, so it normally takes the feminine singular article la when you mean the sauce.

• la salsa = the sauce
• una salsa = a sauce

In Spanish, articles are used more often than in English, so La salsa de tomate... sounds natural.

In Spanish, when one noun describes the type of another noun, the second noun is often left in the singular.

So:

• salsa de tomate = tomato sauce
• literally: sauce of tomato

This is the normal way to say it, even though in English we might imagine it as made from several tomatoes.

This is a very common question. Both ser and estar can be translated as to be, but they are used differently.

Here, está buena means something like:

• tastes good
• is nice
• is good right now / in this context

With food, estar bueno/a is very common for saying that something tastes good.

So:

• La salsa de tomate está buena = The tomato sauce tastes good / is good

If you said es buena, it would sound more like you are describing the sauce as being generally good in quality or as a type, rather than commenting on how it tastes here.

Because buena has to agree with salsa, which is feminine singular.

• salsa = feminine singular
• therefore: buena = feminine singular form of bueno

Compare:

• El tomate está bueno. = masculine singular
• La salsa está buena. = feminine singular

This is called adjective agreement.

Here, buena means good in the sense of tasty or nice to eat.

So in this sentence it does not mean morally good or well-behaved. It is about flavor.

With food, Spanish often uses:

• está bueno/a = it tastes good
• está muy bueno/a = it tastes very good

In Spain, this is extremely natural.

Con means with, so con albahaca fresca means with fresh basil.

The phrase is built like this:

• con = with
• albahaca = basil
• fresca = fresh

So the sentence says that the tomato sauce is good with fresh basil.

In Spanish, adjectives often come after the noun, unlike in English.

So:

• albahaca fresca = fresh basil
• literally: basil fresh

That is the normal word order in Spanish.

Because fresca describes albahaca, and albahaca is feminine singular.

So the adjective must match:

• albahaca = feminine singular
• fresca = feminine singular

Just like:

• tomate fresco = fresh tomato
• albahaca fresca = fresh basil

Grammatically, yes, but it changes the feel.

• está buena sounds more natural if you are talking about how it tastes
• es buena sounds more general, like tomato sauce is good with fresh basil as a general statement

So if you are talking about flavor in a natural everyday way, está buena is usually the better choice.

Yes. La salsa de tomate está rica con albahaca fresca is also natural.

In many contexts:

• está buena = it tastes good
• está rica = it tastes good / it is tasty

In Spain, both are common, though usage can vary slightly by region and person.

Yes, albahaca is a feminine noun, so you say:

• la albahaca
• albahaca fresca

That is why both the article and adjective are feminine.

Most naturally, it means the sauce is good with fresh basil, so basil is being presented as a combination or accompaniment.

Depending on context, it could suggest:

• the sauce tastes good when you add fresh basil
• tomato sauce goes well with fresh basil

Spanish allows that small ambiguity, just as English does.

Normally, Spanish uses the noun structure salsa de tomate, not an adjective.

English often uses one noun to modify another:

• tomato sauce

Spanish usually prefers:

• salsa de tomate
• literally: sauce of tomato

So de + noun is the standard pattern here.