。
It seems she enjoyed the party.
Literal
She [topic-は] party [object-を] enjoyed [seems-ようだ].
~ようだ ('seems / appears / looks like') is one of three main inferential auxiliaries in Japanese, alongside ~らしい (information-based hearsay) and ~みたい (a more casual variant of ようだ). It signals that the speaker is drawing a conclusion from observation or evidence — perhaps the party-goer looked happy, or said something positive about it afterwards. Compared to 楽しんだそうだ ('I hear she enjoyed it'), which reports second-hand speech, ~ようだ leans on the speaker's own perception.