。
She devoted herself to her children.
Literal
She [topic-は] children [matters of-のこと] [target-に] devoted-herself.
[Noun]+のこと is a uniquely Japanese softener: not 'the children' as direct objects, but 'matters concerning the children.' It pads social and emotional contexts where pinning attention directly on the noun would feel too sharp — common with 好きだ ('like'), 心配する ('worry about'), 考える ('think about'). 専念する ('devote oneself to, concentrate on') is built from 専 ('exclusive') + 念 ('thought, attention'); the に-marked target gets one's undivided focus.