Is the word tentativa the same in Brazilian and European Portuguese?

Yes.

The word "tentativa" is identical in meaning, spelling, and grammar in both Brazilian and European Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the vowels are generally more open and the rhythm is more melodic. In Continental Portuguese, vowels are often more closed or reduced (vowel reduction), which can make the word sound more "clipped" to a Brazilian ear.

Brazilian Portuguese Examples

1. Foi uma tentativa de fraude no sistema. (It was an attempt at fraud in the system.)
2. Ele tá fazendo uma nova tentativa de falar com ela. (He is making a new attempt to talk to her.)
3. Essa foi a minha primeira tentativa de cozinhar isso. (That was my first attempt at cooking this.)
4. Teve uma tentativa de fuga da prisão. (There was an attempt at escape from the prison.)
5. Não tive nenhuma tentativa de contato por parte deles. (I had no attempt at contact from their side.)

European Portuguese Examples

1. Foi uma tentativa de fraude no sistema. (It was an attempt at fraud in the system.)
2. Estou a fazer uma nova tentativa de falar com ela. (I am making a new attempt to talk to her.)
3. Esta foi a minha primeira tentativa de cozinhar isto. (This was my first attempt at cooking this.)
4. Houve uma tentativa de fuga da prisão. (There was an attempt at escape from the prison.)
5. Não houve qualquer tentativa de contacto por parte deles. (There was no attempt at contact from their side.)