The key line that makes the whole rest of his character click comes in the first trial. That one that goes “Hope will win at the end. Of that I’m certain.” Everything comes back to this.
Komaeda is certain. He lacks doubt completely. That’s why he can effortlessly pull the trigger on his own head, and pull off the chapter 5 murder trick. Before the first step, he already knew it would work.
His Free Time justifies his conviction by throwing out examples of his extreme luck, both positive and negative, and letting you piece together how those incidents shaped his views on destiny. But most of all, Komaeda’s lack of doubt is justified further by how the world of Danganronpa never proves his understanding of fate wrong. The things he assumed would happen did, in fact, happen, and hope always won at the end of every game (obviously excluding V3, a different world where Komaeda is just a character in a hit PSP game).
Now to the other half of the sentence. “Hope will win”. This is arguably the most important thing for Danganronpa as a whole, not Komaeda specifically. And hope, being the important keyword that it is, needs a definition. And a definition is something the Danganronpa series passionately refuses to provide.
Going by the dictionary, hope is a wish for some unlikely. This ties with the personal definition Makoto utilizes in Danganronpa 1. His idea of hope is to never give up in the face of impossible odds, and he stuck with it until Junko got tired of arguing. However, not every one speaks the same word with the same meaning. When Junko says “hope”, she means the predictable state of the world. When the institution Hope’s Peak Academy says “hope”, it means the talents it fosters and researches. When Munakata says “hope”, it means the opposition and extermination of the terrorist organization named Despair. When Shirogane and Ki-bo say “hope”, it means the continuation of the Danganronpa franchise.
So, Komaeda. What is his definition of hope? What is this that he’s so certain will always wins out? The answer is: all of the above. Our boy is very weak to propaganda. He never second guesses his ability to surmount impossible odds, and has full faith in the status quo that will be reinstated better and stronger after any tragedy. But at the same time, he’s horrendously elitist because he buys into Hope’s Peak propaganda about talent=hope. If he was sent to desolate war zone as a child soldier and was told that hope is actually the divine essence of some grand woman named V'exhness, he would betray his own species without a second thought. He’s the character where the vagueness of definitions is weaponized.
While all meanings of hope are conflated in his mind, I’d say the conflation between hope and talent is the one that shows the most in his DR2 behavior. He humbles himself because, in his propaganda-corroded mind, he can’t be one of the heroes who will make the world a better place because he wasn’t born with that spark that is talent. His relationship with his talent of luck is interesting because it’s undeniably unearned talent, which DR1 uses to inform the player that the system is bullshit. But Komaeda is always unable to doubt his beliefs, so when face with the contradiction of his own “worthless” talents, he has to say his doesn’t instead of seriously questioning the school’s criteria.
tl;dr: Hope will win at the end. Of that he’s certain. If the winner is decided before the match starts, powering up the opponent only means the predetermined winner will play better than they normally would. He lacks talent(hope), but he’s also self-aware that he’s the only one who understands how fate works, so he can adjust the challenge to push the to-be victors to produce more hope. And what is this hope they’re making? Whatever is the most convenient to the ones currently manipulating him.