。
It seems she was happy.
Literal
She [topic-は] happy was [seems-ようだ].
~ようだ ('it seems, it appears') marks inference from observation or evidence — slightly more direct than ~らしい (which leans on hearsay or external information). The past-tense embedded 幸せであった preserves the original time frame: she was happy in the past. The literary copula である takes its past form であった ('was'), as opposed to the conversational だった. The combination であった + ようだ has a definitive, written register.