。
His swing is truly magnificent.
Literal
His swing [topic-は] truly splendid [copula-だ].
スイング is the English loan for a sports swing (golf, baseball). 実に (じつに, 'truly, really') is the adverbial intensifier. 見事 (みごと, 'splendid, magnificent') is the aesthetic judgment. A short sports commentary sentence — compact praise.