Does the saliva reaching the lips and returning (to the mouth) break the fast of a fasting person, even if it was not spat out?

If saliva comes out of the mouth onto one's clothes or hand, or between the lips, and the fasting person intentionally returns it and swallows it, their fast is broken. However, the presence of saliva on the side of the lips while speaking does not invalidate the fast, nor is it necessary to wipe it off. It is advisable to disregard whispers (waswas) about invalidating the fast.