This is the 4799th most frequent Russian word.
звучит
"Sounds" or "is sounding."
Here, 'звучит' is used metaphorically to express how an idea 'sounds' or appears when heard or considered.
Эта идея звучит интересно.
This idea sounds interesting.
In this sentence, 'звучит' literally refers to the quality of sound that is produced by Vasilisa's violin performance.
Василиса прекрасно звучит, когда играет на скрипке.
Vasilisa sounds wonderful when playing the violin.
'Звучит' is used here to describe the auditory impression of a specific word.