A simple (sort of) thought experiment

[kılıç_mehmet]

through methods of torture such as physical torture, psychological torture and all of those methods, person B attempts to make person A's life so bad that person A loses faith in there being a god

I don't understand. Does the person give up his beliefs on his own accord? Or is he forced to recant his beliefs in god due to more torture?

has a high chance of losing faith in religion.

You sound like you have a lot of experience with people who are christians, and were kidnapped and tortured for 2 weeks of 46 years.
I on the other hand say that a christian would be more strongly attached to God, perhaps, with his/her faith being the only thing keeping them alive.

Christian history is full of such martyrs, maybe you'd bother to look up.

in such a scenario, by the direct involvement and influence of person B, person A is now sent to hell for all of eternity even though he did nothing wrong except lose faith in his god after 46 years of severe torture.

Yes, a highly hypothetical scenario. However, I'm sure you've heard of the story of Job, did you not?
Maybe you should read it, and then think up an answer for yourself.

a similar but more boring case could be killing new born babies who are not yet old enough to believe in god and thus sending all of those innocent souls into hell but thats less interesting than this one by far

Not old enough to believe, you say, meaning that they ought to be blameless for dying that young. Catholicism maintains that such babies are sent to purgatory. Protestants on the other hand say they go to heaven directly. How did you come to know that these babies went to hell?