The defense tried very hard to show Renisha had attempted to break into Wafer's house, but the evidence simply wasn't there. And that was all they had -- no breaking in, no castle doctrine, no self defense. It was fairly clear cut when you looked at the actual evidence.
they didnt have to show that she was trying to break in, they had to show that he could have reasonably felt that she was trying to break in. if the jury found him to be credible but didnt believe that she was trying to break in he is still not guilty.