Are weak hadiths considered part of the Sunnah, and is it a condition to believe in them or in hadiths whose authenticity is disputed?

The layperson imitates the trustworthy scholars of hadith, accepting what they have authenticated or deemed good among the hadith, and rejecting what they have weakened. A weak hadith attributed to the Prophet, peace and blessings be upon him, is not to be acted upon, though it is permissible to narrate it for reassurance or regarding virtues. One must be cautious not to give in to obsessive whispers.