This is the 2050th most frequent Russian word.
валерия
"Валерия" is a female given name, Valeria in English.
The word 'Валерия' here is used as the given name of a person.
Валерия учится играть на пианино.
Valeria is learning to play the piano.
Again, 'Валерия' functions as the subject of the sentence, referring to an individual named Valeria.
Валерия всегда была очень внимательна к деталям.
Valeria has always been very attentive to details.
The word 'Валерия' is used in the genitive case, 'Валерии', to denote the origin of the letter from someone named Valeria.