。
She liked taking care of children.
Literal
She [topic-は] children [genitive-の] care [object-を] do [nominalizer-の] [subject-が] liked.
The set noun 世話 ('care, looking after') almost always pairs with する as the verbal phrase 世話をする ('take care of'). To make that whole phrase the subject of a like/dislike predicate, Japanese nominalizes it with の: 世話をするのが好き. Note that 好き is a na-adjective, not a verb; the past form 好きでした is the polite-past copula attached to 好き. The combination of 子供の世話 (the noun phrase) inside 世話をする (the verb phrase) is a layered example of Japanese particle nesting that learners often find puzzling at first.