。
She despises me.
Literal
She [topic-は] me [object-を] is-despising.
軽蔑する ('to despise, scorn, look down on') is built from the Sino-Japanese compound 軽蔑 ('contempt') + する. The kanji break down nicely: 軽 ('light, slight') + 蔑 ('disregard') — literally 'lightly disregard.' The progressive ~ている marks an ongoing emotional attitude, not a single act — exactly the same use as 知っている ('knows') or 愛している ('loves'). For state-of-mind verbs in Japanese, ~ている is the standard form for the held attitude.