When do I use 确定 versus 决定？ The two words mean approximately the same thing but I find that there is a nuance I'm missing in terms of the appropriate context to use one or the other. How should I think about the difference between these two?
确定 means 'be sure' or 'comfirm'/'be confirmed'. 我确定他会回来的.(I'm sure he will be back.)

决定 (v) means 'decide to do'. 我决定做...(I decide to do something...)

决定 (n) means 'decision'. 我终于做出了决定.(Finally, I made my decision.)