Jennifer doesn't know who to believe, but the lipstick on William's neck is just a little to red to ignore, much as he might like her to. The more she tries to make sense of the stories, the more it feels like she's repeating mistakes from her past, and that's something she wants to avoid at all costs, no matter how much it might hurt.
William does what he can to juggle all the secrets, stories, and his brother's antics, but in the end it proves to be his undoing. Following Edward's advice, he takes a chance and reveals things he'd really rather keep to himself. Whether the risk and the fallout will be worth the price he must pay remains to be seen.