。
Does she still want to come to the party even now?
Literal
She [topic-は] now-even still party [in-に] participate [want-to-third-person-たがる] [explanatory-のです] [question-か]?
~たがる is Japanese's solution to a grammatical sensitivity: ~たい ('want to') is an i-adjective describing the speaker's own desire, but using it for a third party would claim direct access to their mind. So Japanese has ~たがる, an objective inferential — 'shows signs of wanting to' — for third-person desires. The のですか frame combines the explanatory の with the polite question か, asking for confirmation or clarification with a hint of surprise. 今でも + まだ together stack 'even now' with 'still,' doubling down on the surprise.