I was 'secure in the belief/knowledge' that I had done all I could. [=I felt confident because I believed/knew that I had done all I could]
They are 'financially secure'. [=they have enough money to live on; they do not have to worry about money]
You can access your bank account online using a 'secure' [='secret'] password.
(..) Fury, you son of a bitch. Oooh! You kiss your mother with that mouth? Altitude is and climbing. Lifeboats secure to deploy. Disengage in , ...take 'em out. This is SHIELD? This is what SHIELD's supposed to be. This is not so bad. Let's load 'em up. (..)2015 Avengers: Age of Ultron
(..) - He's a blur. In fact, I still haven't. Clint's hit pretty bad, guys. We're gonna need evac. I can get Barton to the jet. The sooner we're gone the better. - You and Stark secure the scepter. - Copy that. - It looks like they're lining up. - Well, they're excited. Find the scepter. (..)2015 Avengers: Age of Ultron