That time travel will occur is difficult because of the fact that we have no way to know that it will happen in the future, but the fact we were able to guess that in the future this thing forward, it might actually happen.
The time travel is possible, it is really difficult, because we never know when it will occur in the future, however, we were able to predict that in the future this is likely. may actually occur.
The time travel will occur that is difficult, because we never know how much it would happen in future, but the fact we were able to predict that in the future this may occur.