A realidade é simples.

A is the definite article meaning the.

In Portuguese, it is very common to use the definite article with nouns, even in cases where English might not. So A realidade is literally the reality.

In a sentence like this, Portuguese prefers A realidade é simples rather than just Realidade é simples.

• A realidade = the reality
• é = is
• simples = simple

Without the article, the sentence would usually sound unnatural in normal speech, unless it were a title, heading, or a very stylized statement.

Yes, realidade is a feminine noun.

You can tell here because it uses the feminine singular article a:

• a realidade = the reality

Also, many Portuguese nouns ending in -dade are feminine:

• a cidade = the city
• a verdade = the truth
• a liberdade = freedom
• a realidade = reality

So realidade is feminine singular.

Portuguese has two verbs that can both translate as to be: ser and estar.

Here, é is from ser, and it is used because simple is being presented as a general, essential, or defining characteristic of reality.

• A realidade é simples. = Reality is simple.
  This sounds like a general truth or statement.

If you used está, it would suggest a temporary state or condition:

• A realidade está simples.

That sounds odd in most contexts, because reality is not usually thought of as being temporarily simple in that way.

So é is the natural choice.

É is the 3rd person singular present tense of the verb ser.

So:

• eu sou = I am
• tu és = you are
• ele/ela é = he/she is
• a realidade é = reality is

The accent matters:

• é = is
• e = and

So é and e are different words.

Good question. In Portuguese, many adjectives change form for masculine and feminine:

• simples is one of those adjectives that does not change between masculine and feminine.

Examples:

• um problema simples = a simple problem
• uma solução simples = a simple solution

So even though realidade is feminine, the adjective stays simples.

It also happens that simples has the same form in the plural too:

• a realidade é simples
• as realidades são simples

So simples is very convenient: same form for masculine, feminine, singular, and plural.

In European Portuguese, a natural pronunciation is approximately:

a re-a-li-DA-de é SIM-ples

A few useful points:

• realidade has stress on da
• é is pronounced like an open eh
• simples in European Portuguese often sounds closer to SIM-plsh than the clearer Brazilian-style ending

A rough English-friendly approximation might be:

uh reali-DAH-duh eh SIM-plesh

But that is only approximate. European Portuguese often reduces unstressed vowels quite a lot.

In normal Portuguese, this would usually sound incomplete or unnatural.

The standard sentence is:

• A realidade é simples.

Portuguese often uses the article where English does not. This is especially common with general nouns.

You might see article-less forms in:

• headlines
• notes
• poetic language
• very compressed philosophical writing

But for a learner, A realidade é simples is the safe and natural version.

Yes, but that means something different.

• A realidade é simples. = Reality is simple.
  Here, simples is the adjective after the verb é, describing reality.

• A simples realidade = the simple reality / the mere reality
  Here, simples directly modifies the noun realidade.

So the structure changes the meaning:

1. A realidade é simples.
   Statement about reality.

2. A simples realidade...
   A noun phrase, often meaning something like the mere reality or the plain reality.

So you cannot freely swap the order without changing the meaning and grammar.

The structure is:

article + noun + verb + adjective

So:

• A = definite article
• realidade = noun
• é = verb
• simples = adjective

This is a very common pattern in Portuguese:

• A vida é curta. = Life is short.
• A resposta é clara. = The answer is clear.
• A situação é difícil. = The situation is difficult.

So A realidade é simples. is a very standard sentence pattern.

Not exactly.

• simples = simple
• fácil = easy

These ideas are related, but not the same.

For example:

• A explicação é simples. = The explanation is simple.
  It is not complicated.

• O exercício é fácil. = The exercise is easy.
  It is not hard to do.

So in A realidade é simples, simples means not complex, not necessarily easy.

You would make the noun, article, and verb plural:

• As realidades são simples. = The realities are simple.

Changes:

• A → As
• realidade → realidades
• é → são
• simples stays simples

So this sentence is also a useful example of how plural agreement works in Portuguese.