Ivan, good question! Numbers 1 and 2 are correct and do sound natural, either one would work fine. For example if someone asks you "Ivan, are you going to the game tomorrow night?" "Ivan, are you going to Isabel's birthday party tonite?" You mean that you hope to go, you will try to go, but you are not certain that you will actually be there. Numbers 3, 4 and 5 fit more of a situation of you questioning your ability to do something. For example "Ivan, can you help me fix my computer?" You mean that you are willing to try, to make an effort to help me, but you might not succeed, maybe you do not have much experience or training to do it. You are telling me that it may be a failure, you might not succeed, you might not have good results, it may even be a disaster! (haha) Natural ways to express Numbers 3,4 and 5 could be: "I'll try, but there is no guarantee that I'll succeed" or "I'll give it a try, but it might not work out."

Hello Ivan! I think it depends on the context. I am not sure what you mean to say. Number 1 is a natural sentence that you could say if you are intending on meeting someone or have some arrangement. Number 2 is also possible(apart from the typo of writing I two times) Number 3 isn't correct "if I will succeed" Number 4 possible but means not natural Number 5 not correct. I hope that helps, Conor