But you never had a contract with me that you will be patient with it. You say that you are patient you can endure, that you may not have patience to it anymore.
But you can not always promise me that you will be patient with it. You just said that You will be patient as you can tolerate. It shows that you can not bear with it anymore.
But you never promise me that you will bear with it. You say that you will not tolerate as much as you can endure. So that you may not tolerate it any more.