。
She's living a comfortable life in the countryside.
Literal
She [topic-は] countryside [in-で] comfortable [possessive-な] life [object-を] is-living.
安楽な生活 ('comfortable life') uses 安楽 (comfortable/at ease), a Sino-Japanese compound that's slightly more formal than 楽な. 生活を送る ('to send/pass one's life') is a common collocational verb for 'to live a life' — more natural in written Japanese than 生活をする for describing an ongoing lifestyle. ~ている marks the present ongoing state.