Tally chose the smoke over being pretty. You can see
hints of this coming simply from her journey to the Smoke, but when she gets there and is finally used to life there she decided that she couldn’t give them away. She’s always wanted to be a pretty, and this doesn’t exactly prove confidence in her looks, but in her choices. Tally knows this is the correct choice, taking away David’s home is not what she wants, so she throws the pendant into the fire. Not knowing the possible consequences of her actions.
“Seems like you didn’t eat much at all, for such a long trip.” (227) Croy confrontation of Tally lying about her trip is an example of her confidence. She quickly covers it up with another - more believable - lie. Tally’s confidence helped her get through some sticky situations in which the old Tally would have given herself up in an instant. Her confidence has made her a lot trickier and quick-thinking.