。
She's settled down with marriage now.
Literal
She [topic-は] now [as for-では] married-and body [object-を] is-hardening.
身を固める is a vivid set phrase: 身 ('body, self') + 固める ('to harden, to fix in place'). The metaphor is of stabilizing one's life position, traditionally through marriage but also through career or settling down in some lasting way. It carries a slightly old-fashioned, gravitas-heavy tone — the kind of thing said about someone reaching adulthood milestones. The te-form 結婚して chains in the means: 'by getting married, has settled down.' ~ている here gives the resulting state of having stabilized.