。
She doesn't want to date Bill.
Literal
She [topic-は] Bill [with-と] date-want-not [quotative-と] is-thinking.
交際する ('to associate with, date, keep company with') is broader than 'date' in English — it can mean a romantic relationship, but also an ordinary social or professional acquaintance. The と before 交際する is the comitative ('with'), marking Bill as the partner in the action. The ~たい form turns a verb into 'want to do'; its negative form ~たくない (here in plain non-past) reports the speaker's understanding of her wish, not a stated fact. The whole inner clause is then quoted by と and reported as ongoing thought (~と思っている), giving an indirect, third-person description of how she feels.