Donația este mare.

Because donația is the definite form of the noun.

• donație = donation
• donația = the donation

Romanian usually puts the definite article at the end of the noun, not as a separate word like English the.

So:

• Donația este mare. = The donation is big/large.

Este means is. It is the 3rd person singular present form of a fi, which means to be.

So the sentence breaks down like this:

• donația = the donation
• este = is
• mare = big / large

Yes. E is a very common shorter form of este in everyday Romanian.

So both are correct:

• Donația este mare.
• Donația e mare.

The version with este can sound a little more full or formal, while e is very common in normal speech.

Because in this sentence mare is a predicate adjective: it comes after the verb este and describes the subject.

This is normal Romanian word order:

• Donația este mare. = The donation is large.

Compare that with an adjective directly modifying a noun:

• o donație mare = a large donation

So:

• donație mare = noun phrase
• donația este mare = full sentence

Yes, it does agree, but in the singular the form mare is the same for both masculine and feminine.

Examples:

• băiatul este mare = the boy is big
• fata este mare = the girl is big

In the plural, it changes to mari:

• băieții sunt mari = the boys are big
• fetele sunt mari = the girls are big

So in your sentence, mare is correct for feminine singular.

Because in Romanian, when an adjective comes after to be and functions as a predicate adjective, it does not take the definite article.

The noun carries the definiteness:

• donația = the donation

The adjective just describes it:

• mare = big / large

So:

• Donația este mare. = correct

But if the adjective is inside the noun phrase, you still usually mark definiteness on the noun, not on the adjective in this kind of simple structure:

• donația mare = the big donation

A simple learner-friendly pronunciation is:

do-na-tsi-a

A few useful points:

• ț sounds like ts, as in cats
• a is a clear ah sound
• the stress is on ți

So donația sounds roughly like do-na-TSI-a.

Yes, but the normal, neutral order is:

• Donația este mare.

Romanian can change word order for emphasis, but that usually sounds marked, literary, or contrastive. For a beginner, the standard order is the best one to use.

Not always. Mare can mean big, large, or sometimes great, depending on context.

In this sentence, with donația, the most natural English choices are usually:

• The donation is large.
• The donation is big.

In some contexts, English might even express the idea more naturally as The donation is generous, but that depends on interpretation, not on the literal meaning of mare.

The indefinite version uses donație without the definite ending, usually with o:

• O donație este mare. = A donation is large.

But in isolation, this can sound a bit unnatural unless the context makes it clear which donation or what contrast you mean.

Most often, if you are talking about a specific donation, Donația este mare is the natural choice.