I want to start game developing but I need help choosing what programming language to learn. I already tryed Lua,Java,C++ but not Rudy and Python... So here is my question, I need the pros and cons on Ruby and Python and your recommendation. I need something I feel comfortable with.
I don't really know Ruby, and only a bit of Python (as much as I need). But I definitely say, go for Python. Python is great and is definitely becoming an landmark language in that space (high-level interpreted languages). I can't give you technical arguments why, all I can do is give you my impression, which is that Python is everywhere and super important, while Ruby remains obscure and seems to be "losing the fight".
Also, I don't know what you think that these languages will do for you in terms of game-dev, but I don't think it's much. Serious game-dev is dominated by C++. The "fun apps" space is a bit more diverse (Obj-C, Java, Python). But still, the primary focus for game-dev is C++, and it will remain so probably for a long time. And that brings me back to Python, one of the great advantages of Python is that it interacts very well with C/C++ libraries, and so, it's a great language to use as a high-level layer sitting on top of the serious heavy-lifting code that you write in C/C++.
Don't forget Gmod though, it was made in Lua.
There is no "best".
Therefore asking for "the best" is a by definition useless exercise.
There might be something that's more appropriate for specific purposes in specific scenarios than something else, but you never tell us what your specific scenario is so again it's impossible to answer your question.
Ruby and Python are pretty similar in their capabilities, so it's mostly a question of individual preference combined with integration with whatever other tools you have selected to use.
For me, that means Ruby is overall the more likely option when and if I need a scripting language, simply because I have the infrastructure to support it already in place.