This is the 8322nd most frequent Polish word.
paulina
"Paulina" is a Polish female given name, equivalent to "Pauline" in English.
In this sentence, 'Paulina' is used as a proper noun, which is the name of a person.
Paulina jest świetną przyjaciółką.
Paulina is a great friend.
Here, 'Paulina' is again a proper noun, referring to a person named Paulina, acting as the object of the sentence.
Spotkałem się z Pauliną wczoraj.
I met with Paulina yesterday.
In this context, 'Paulina' is used to emphasize the actions or behavior of the person with this name.