What Edna scared is not because Eli will get mad when he know the truth.
Edna scared that Eli would feel guilty for destroying her family and undirectly caused Edna to live her life in torture as slave/maid before meeting Eli. Edna scared that Eli will get his heart crushed by guilt. But also because Edna was supposed to be his enemy, Edna also scared that Eli would turn to hate her.
But to be honest, all this can be solved easily with a good honest talk together.
Especially this manga which don't really dragging things on, this time problem probably will be solved within 2-3 episodes. While Count Polit problem will be solved within 3-5 episodes.
so..the moment of truth has arrived!!!!
I bet she had hoped for a better situation and place to tell him the truth but right now neither is in her favor.. i just hope he doesnt feel being deceived by her all these years.. she honestly love him and forgave him for destroying her family whtsoever.. she even gave him a family ..just wht else is there to prove? i hope n hope nothing goes wrong!