What is Emma Frost's Weakness?

Answer 1

I'd say her past. After she killed her sister, Adrienne, she became a severe alcoholic. Besides that, she's never quite been able to escape her past history as a villain of the X-men, affecting many members trust in her. She has also proven to be a more, shall we see, flexible telepath when it comes to the moral nature of the usage of her gifts. This also leads to distrust.

When talking about fighting weaknesses, she has no access to her telepathic powers when she is in her diamond form.