How do You Activate a Thought ?

Good evening,

I understand that to deactivate a thought that no longer serves you, you have to identify it, feel the emotion related to it, and not react to it a certain number of times.

However, how do you activate a thought ? I understand that a thought is activated when you feel it, take action and get the result.

For example, I used to be anxious about the future, but when I think « I trust the future », I feel confident about it so that works. But when I think « I am worth it », I feel nothing but anxiety. How could I activate it ?