The season finale of Bones was definitely a game changer and if you felt like Brennan was a little apprehensive about telling Booth the good news, your right! Tempy was genuinely surprised and taken aback by Booth's happiness. Here's what EP Stephan Nathan had to say about that moment.
"There was a little something in that, she's spent six years slowly becoming more and more in touch with a softer side of herself. And this was sort of one final emotional touch from Booth that says, 'You can enjoy this. You can accept this as the most wonderful thing in the world.'"
Source: TV Guide