Not trying to be rude, but if you've tried and actually FAILED to learn Objective-C multiple times, then you will have a much bigger problem with actually learning the Cocoa framework yourself. Objective-C does have a non-standard syntax, but its barrier of entry for actual learning is purely psychological and not technical.
I suggest http://www.raywenderlich.com/ and his fantastic books with examples. While I actually think I've been doing Objective-C longer than most of his writers, when there is some area I haven't worked in yet they usually have a high quality, simple to follow example on how do do a thing that's a great jumping off point to getting going and then understanding further once you get the main thing in front of you.
Maybe the mistake could lie in starting with Objective C without first learning C? I'm thinking that a reasonably solid C foundation helps a lot in understanding why and how Obj-C works.
I went straight from a CFML/Java/Javascript web developer to picking up Objective C in a week. I had some coaching from a C/C++ expert, who learned ObjC on the fly and wrote a first draft of an app I designed, but from there I worked out how to solve my own problems and eventually became a moderately high skilled ObjC developer.
I have subsequently leveraged that ObjC experience to become somewhat proficient in plain C, a skill I appreciate today and something I might never have learned otherwise.
I learned Objective-C before I learned C, back in the early 90s. Before that I'd learned Basic and Pascal. Objective-C clicked with my brain pretty easily.
While knowing C certainly helps, it is not essential to learning Objective C, at least it wasn't for me. If you try first to understand it at a high level, then it is very doable (and fun!).
