Since it was April fools, I'm going to tell my assistant she got a promotion and pay raise; the next day I'm going to call her and tell her "April fools!"
Why would you get their hopes up like that?
Who cares. It's funny.
Promotions and raises are not to be the subject of a prank. Telling your assistant lies about her career is not funny. Show her more respect as a fellow co-worker.
I'm going to, this will be fun.
You need to tell them the truth as soon as possible. It is not okay to give false hope like that. It is not funny to joke about things like that.