"Made out" is not used to mean "try to prove." It means "behave like" or "pretend," just as the previous person explained. It also means to "show." For example, He made out that he was an expert, and I realized it was true. The first meaning is more common. How do we know? The context. Think about which one makes sense with the sentence/s around it. I hope that helps.

"made out" here means "behaving like". It can mean either, unless you know for a fact whether the person actually is innocent. "He made out that he was innocent, but I saw him steal the money." "He made out that he was innocent, and I believe him because I've known him my whole life."

Sadly, I disagree with the previous commenters: "made out" can definitely mean "discovered" or "deciphered". "He squinted at the strange letters in the dark cave, and eventually made out the word "Beware!"". "It seemed obvious that Bob was guilty, but, after months of gathering and analyzing evidence, I began to make out that Bob could, in fact, be innocent." In the sentence you gave, it is very unlikely that this is the meaning, but without more context I can't be sure.