It won’t simply be her saying “he solicited me.” There will be information that corroborates this; I’m guessing in the form of text messages. Mobsters have been convicted on the word of other mobsters. Killers have been convicted on the word of other killers. This sort of thing happens all the time. The jury doesn’t have to like her, and they don’t have to totally believe her. All that matters is that they believe that PF is guilty.