Confidence, like contentment, doesn't come naturally. We aren't born with it; it is a learned trait. The Bible teaches us that confidence, unfortunately, is learned in the school of hard knocks.
From the very first part of that passage, we're thrown for a loop. Glory in tribulations? Seriously? Who in their right mind is happy about hard times, trials, or difficult circumstances? The one who follows through and understands the rest of the passage. It's all about the process taking place. We don't glory in trials because we enjoy them. We glory in them because they are helping us become the best version of ourselves. We rejoice in the hard times because that's how we increase our faith. Tribulation brings patience which brings experience which brings hope (confidence).
The Greek word translated as "experience" in this text is elsewhere translated as "experiment." For me, that actually makes it a little easier to wrap my head around. Each trial in my life is an experiment--an opportunity for me to see God in action. That means each trial gives God a chance to prove His faithfulness and ability. It's a test, an experiment. Each time God comes through, He gives us another reason to trust Him.
Faith and confidence aren't fostered and grown in the good times but rather in the bad. Watching God move mountains, part seas, heal the sick, and answer prayer brings about a feeling of trust. The more He does, the more we feel we can rely on Him. And in that respect, the bigger the trial, the better because if He can conquer the giants, He can certainly take care of the everyday stressors.
Our problem is that we want confidence without the tribulation, patience, and experience. We want to simply be gifted with a faith-filled heart, but it doesn't work that way. Before we can be confident in God, we need to see what He can do. But before we can see what He can do, we need a problem for Him to solve, right? It's like the old Florida Boys' song states, "Without a valley, how would I ever know?"
Are you going through a trial today? If so, take heart in the fact that confidence is right around the corner. God will get you through, and in that, He will, once again, prove Himself worthy of your trust. Hang in there and rejoice!