How can we be sure our specific Christian confession is true, when every other Christian group claims that it's not? I'm a recent convert to Eastern Orthodox Christianity, but I've started to doubt the faith recently, and I’m really desperate for help. The doubt I have is really one I've had since the beginning of my conversion process, and one I have never seen anyone satisfactorily answer, and it is currently the biggest impediment to my fully believing, namely: what if I'm wrong? And I don't just mean about Christianity, although that's certainly a concern too, but just about the particular Church I belong to.

Historic Christianity (and all churches that currently exist from apostolic times, i.e., the Roman Catholic Church, Eastern Orthodox Church, Oriental Orthodox Church, Assyrian Church, etc.) all claim to be the "one, holy, catholic, and apostolic Church" founded by Jesus Christ, and outside of which there is no salvation. Similarly numerous Protestant groups claim that if you don't adhere to their interpretations of scripture, you're most certainly hellbound. 

And my problem is this: why must I become a historical and theological scholar to believe in Jesus? Deciding between the historic Churches (Roman Catholic, Eastern Orthodox, Oriental Orthodox, Assyrian churches, Protestant, etc.) requires immense amounts of historical and theological study, and at the end of the day I could still be wrong. There will ALWAYS be that doubt in my mind, “what if you’re wrong about X doctrine, and you’ve been a part of the wrong Church this whole time,” no matter where I end up, this doubt is always going to be there. There will always be people claiming that I don’t “really understand” some doctrine or historical event, and therefore my faith is completely wrong and I’m essentially damned.

Christians talk a lot about us “submitting to the Truth, and not claiming it for ourselves,” but how am I supposed to do that if everyone is claiming they have the one Truth, and everyone is saying everyone else is just being deceived by demons or something? How can I submit to the Truth, if I don’t know what it is? Even if God decided to “reveal” something to me, how could I be sure it’s of God? At the end of the day, no matter what I believe, I’m always just relying on my own interpretation of the data. What I believe is decided by me, no matter how much “evidence” I may have for it, I’m a fallible human being and I could totally be wrong. I’m not a theology expert, I’m not a historian, I’m not a philosopher, and yet even if I was, would it matter? There are scholarly theologians, historians, and philosophers who all think they have the one Truth and everyone else is wrong, while completely contradicting one another. The same is true of all historic forms of Christianity that have canonized saints claiming that their Church is only right one, and all those outside are damned. 

We can’t even rely on this notion that “well our saints perform miracles, and I’ve witnessed some of these miracles,” because the same holds true in Roman Catholicism, Oriental Orthodoxy, Assyrian Orthodoxy, and even non-Christian religions, and they can’t all be right. In fact, according to each group, they’re the only ones who have valid miracles and everyone else is just being demonically deceived. I really don’t know if there’s any actual response to this question, and so far I haven’t found it, and I don’t expect to find it from anyone here but I’m desperate here. I really want to believe, I really do, but if I can’t be sure, what’s the point?
Very simply put, your assumption here is wrong:


  ... founded by Jesus Christ, and outside of which there is no salvation.
  Similarly numerous Protestant groups claim that if you don't adhere to
  their interpretations of scripture, you're most certainly hellbound.


Salvation is in Jesus Christ, not the church.  As a result of sin, everything on this earth is corrupt in some way, including the institutional church.  As a protestant, I would not condemn you for being an orthodox Christian.

Truth is in the Bible, not the interpretation.  Pursue discipleship - following Jesus.  Trust the work He did for you on the cross.  Join a church as a means of fellowship and serving Jesus.  Try to find the truest doctrine you can, but don't think that you will be condemned if your church isn't perfect.

If you have doubts, pursue them.  The study of apologetics can help you reason through them.