Personally, I thought Marlena’s demeanor was suspect. She shows up at Kristen’s room and wants to clear the air. In my opinion, she went about it wrong. She should have told Kristen that she had time to think and realized that Kristen’s intentions with Brady are real, and she wants to make peace with Kristen. Instead, Marlena seemed too anxious, to eager to "talk about the situation". Everything about Marlena screamed "I’m going to expose you." One thing Kristen is not. it is stupid.
But I don’t know how the note will make Brady realize what Kristen is up to.