You perhaps believe that you have a genuine faith but actually believing something is not the same as to know. It can happen in the future that you lose it, you never know. Other people had faith but they lost it. According to your theology they were not saved because their faith was false. Arminian theology hasn't such problems.
Faith is faith.
I know that I am saved because I believe in Christ. But I can lose my faith and by this token I can lose my salvation. It is written that we must continue in our faith. It teaches no such thing. It says that you have been reconciled if you continue in faith.