。
She berated him for forgetting his promise.
Literal
She [topic-は] he [subject-が] promise [object-を] forgot [nominalizer-こと] [object-を] berated.
A nominalized embedded clause: 彼が約束を忘れた ('he forgot his promise') is wrapped in こと and marked with を as the object of ののしった ('berated, cursed at'). ののしる is a strong verb of verbal abuse, often used in legal or news contexts for the act of hurling abuse at someone. Note the embedded subject takes 彼が, not 彼は — Japanese restricts は to matrix-clause topics, and embedded subjects almost always default to が.