"Born with the nature of" is a pretty good definition. You've got the idea.

"Born" isn't quite right. I can say "iron is inherently magnetic," for example, and it's not clear how or when iron is "born."

Do you know the word "intrinsic?" "Inherent" and "intrinsic" are synonyms.

"Inherent" refers to characteristics that are part of the basic nature of something. They are built-in. They aren't added. They can't be changed.

Examples:

Money is not inherently evil. It can be used for good purposes or bad.

Anything that stores a lot of energy in a small container is inherently dangerous; this includes gasoline and lithium.

The court reasoned that Wikipedia entries are inherently unreliable because they can be written and edited anonymously by anyone. 

The breed of dog known as the "pit bull" is controversial. Some people think the breed is inherently dangerous, and some cities have banned them.

Cola beverages are not inherently brown. Caramel coloring is added to them to give them the color that people expect.

According to Noam Chomsky, certain features of language are not learned. They seem to be inherent in the human brain.

According to the Christian doctrine of "original sin," human beings are inherently sinful.

What are you having trouble with? I will try to explain, although I can't relate it back to Portuguese

Inherent and inherently mean the same thing, except "inherent" is an adjective (describes a noun), and "inherently" is an adverb (describes verbs or adjectives).

They mean something along the lines of "by its very nature", "fundamental", "naturally"

Examples: (the word that inherent/inherently describes is bolded)

        Because the building was built on soft sand, there was an inherent weakness in its design.

        Skydiving is inherently risky.

Risky is an adjective, so it uses the adverbial form of "inherent" to be described. Weakness is a noun, so it uses the adjective form.

If you tell me what you are confused about then maybe I could explain it better :)