。
She didn't marry anyone.
Literal
She [topic-は] anyone [with-と][also-も] did-not-marry.
誰とも + negative is the universal-negation pattern with the comitative と ('with') at the head: 'with no one.' 結婚する ('to marry') takes the spouse with と (the collaborative/comitative reading), not に — the marriage is conceptualized as a joint action rather than something done to someone. 田中さんと結婚する ('marry Tanaka').