。
She married Hiroshi reluctantly.
Literal
She [topic-は] reluctantly Hiroshi [with-と] married.
嫌々 (often written 嫌嫌 or いやいや) is the reduplicated form of 嫌 ('disliking, unwillingness'), creating an adverbial 'reluctantly, against one's will.' Tacking on ~ながら gives it the concessive flavor 'while disliking it,' the same ~ながら family used in phrases like 残念ながら ('regretfully'), 我ながら ('even for me'), 失礼ながら ('if you'll forgive me'). The と in ヒロシと結婚した is the comitative — when you marry someone, you grammatically marry 'together with' them. Rendering Hiroshi (ヒロシ) in katakana rather than 弘 or 浩 is a minor stylistic choice that gives the name a slightly distanced or stylized feel.