The phrase "dark sinful past" brings to mind a history of immoral and illicit behavior. However, there are many other ways to describe a past filled with regrets. Some synonyms for "dark" could be murky, shadowy, bleak, or ominous. "Sinful" could be replaced with wicked, depraved, immoral, or corrupt. And instead of "past," other phrases could include prior transgressions, former wrongdoings, or past mistakes. Choosing different words can convey the same message in a more creative and nuanced way. It's important to acknowledge and learn from our past, but it's also important to choose positive language when reflecting on it.