I don't think much ...... because she can't divulge any of that information but she will know what a rat Sami is.
At this point it is hard to say what Marlena will do with the knowledge that she now has. Due to her oath as a doctor she can't reveal much to anyone about what was said with Gaby, but the way it all went down today it is pretty clear that Sami knows that Gaby told on them all. I would say this may be part of how and why EJ, Sami, and the two kids leave Salem this fall.
I don't believe Marlena will tell what was told to her. As far as Sami I bet it didn't surprise Marlena a bit. She knows what kind of a daughter she has.
Marlena is starting to annoy me. Sorry if that doesn't help but MAYBE she will keep her mouth shut for a change.
I just loved the scene with Sami after Marlena found out about Gabi, Kate and Sami throwing Nick in the river. What do you think is going to happen now Marlena knows?