When I go to a doctor and he finds a problem with me, he frequently gives me a list of options for me. Occasionally, a doctor gives his patient only one option. Sometimes there is but one treatment for a ailment and there is no alternative, other than to let the illness take its course.
When Jesus prayed in the garden to “…let this cup pass from me.”, He probably already knew the answer. Yet, for us, He still voiced the prayer. Also, there was likely a last minute hope. Let’s face it. He was facing a terrible ordeal, and that is a gross understatement.
So it was that He went to the cross to pay for our sins. Don’t you know that if there was another way, God would have answered His prayer and provided another way. The fact that He went to the cross is proof that there was no other way.
Therefore, if anyone tells you that there are other ways into heaven, you might remind them of this. Our sickness is sin and the only cure was and is his blood. There is no other option. There is no other way. If there was, it would make His death pointless and it would mean He did it all for nothing.
Moreover, nothing can be added to it. Nothing can be taken away from it. Any attempt to add to it, is to imply his death is not enough. Any attempt to add to it, is to imply that it is possible to add anything to it.
Many say that it is pride to say that I am going to heaven and I know it. I say that it is a lack of faith for me to say less. Jesus’s provided my healing and nothing else. Nothing else will.
 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:  Not of works, lest any man should boast. (Ephesians 2:8-9)
A side note: It is impossible to earn a gift. If it is earned, then it is no longer a gift. Therefore, it is impossible to earn the gift of salvation. It must be received as a gift through faith. Any other teaching is deceit.
Remember. You might not like the rules, but neither do you make them. There is no way any of us will ever change them.