When someone (usually a friend) convinces you that you you are attracted to someone else by continuously telling you that you like them. After weeks (days, if the friend is an extremely good peter-er) of constant bombardment, you start to believe it yourself and by then, you actually do like the person.
Peter: Dude, you like her.
Matthew: NO I DONT.
Peter: Dude you totally like her.
Matthew: Holy shit, i do.