credence

credence     [KREED-ns] 

noun. belief in or acceptance of something as true

"Was there any credence to the old advice of giving the lid of your soda can a rinse, or at least a good wipe with a towel or napkin?  It is actually a pretty good idea to do so."

"None of the later historians has given any credence to this theory."

“She gave credence to the gossip."