The only way to achieve the impossible, is to believe that it is possible
However, it will not always be simple!
Have you watched the film Alice through the looking glass?
At the start of the film, Alice had encountered a difficult situation; the people around her were in panic and were unaware of what to do.
One person said to her that it would be impossible to have a solution to the situation.
However Alice said the only way to achieve the impossible, is to believe that it is possible.
This sentence means that whatever the problem is, you just have to find the answer to it.
But of course it may not always be simple to do so.
It just like when you encounter a problem, never try to run away or to ignore it,
instead try to take some time and understand, that way you would be able to find answers and solutions to it.