。
She was satisfied with the result.
Literal
She [topic-は] result [target-に] was-satisfied.
満足する ('to be satisfied') takes its target with に — the same に that marks objects of inward-facing emotional and mental verbs (~に夢中, ~に没頭, ~に頼る). The whole pattern [N]に満足する is the standard way to say 'satisfied with X.' For dissatisfaction, swap to 不満 (a noun, used with を持つ 'hold dissatisfaction with') or stick with the negative 満足しない. The succinctness of this sentence — five words doing the work English needs eight for — is a nice illustration of how Japanese particle marking compresses information.