。
She can play the piano very well.
Literal
She [topic-は] very skillfully piano [object-を] play can.
弾く is the verb for plucking or striking strings — the right choice for piano, guitar, koto, and other stringed instruments (despite a piano being struck rather than plucked, it inherits the 弾く verb because of how Japanese conventionalized music vocabulary). Drums get 叩く, woodwinds and brass get 吹く. Knowing which verb pairs with which instrument is itself a small chunk of cultural literacy.