Why Did Wanda Throw Geraldine out?

The S.W.O.R.D. logo hanging around her neck - rather conspicuously giving her game away - confirms in Wanda's mind that she too belongs to whatever invading force the beekeeper came from. That's why she's thrown out, with Scarlet Witch's tell-tale magic swirling around her.

Why did Wanda kick Geraldine out?

Right now, the popular theory is that Geraldine was sent to Westview to monitor Wanda and the world that either Wanda or someone else created. When Geraldine told Wanda about how Pietro was killed by Ultron, Wanda kicked her out of Westview.

What is up with Geraldine in WandaVision?

Based on the end of Episode 3 of WandaVision, when Geraldine is ejected from Wanda's universe and plopped into a field in New Jersey, it's safe to assume she is actually Monica Rambeau. Plus, president of Marvel Studios Kevin Feige confirmed to The Wrap that Geraldine is, in fact, Monica Rambeau.