Re: if rin not died then obito become a evil man(tobi)??
it depends, this is a question of whether is she the reason or the cause.
> the reason is the logical explanation of why has sth happened, which may or may not be honest and true.
> a cause is simply what created the situation.
if you think she created the situation, then she is the cause of it. but if she is (one of) the explanation(s) then she is the reason. which means, for example, that if Rin is the reason then sth else could have happened and triggered the same or a similar effect, it just happened and it was Rin. but if she is the cause then she and her death created the situation.