''Faking it until you make it'' is sure to lead to either self-delusion and/or extremely cringeworthy social behaviour.

Genuine self-belief and self-assuredness (aka ''confidence'') can only be achieved by being satisfied by your abilities from an internal perspective.

It's impossible to create genuine, believable ''confidence'' about things which you know that you are lacking in, unless you enter into the realms of delusion.