Asalamualaykum,
If you’re making wudu and you’re up to the putting water in your mouth and you spat the water out then swallowed (whether it’s saliva or you just felt like you needed to swallow even if it’s nothing) but you’re not 100% sure if you swallowed the water or it could’ve just been your saliva does that invalid your fast? And what if after you spat out the water then swallowed your saliva and you’re doubting if you swallowed water or not, does that also invalid your fast?