Where's the line?

Where is the line at in order to be saved ?

I ask this question because there have been mormons coming to my house. The say that they believe Jesus is God's son and that he died on the cross and rose again. They believe he is the Christ. But is that enough ? Talking with them we came to some disagreements and in the midst of trying to prove them right or wrong I wondered does it matter who is right or wrong. as long as we believe that much does it matter what we believe about heaven or hell or before and after life. Does any of that really matter?
I wonder if it does. But if it does then i want to fight for the truth. If it matters then i want to tell people the truth. But if it doesn't then i will just make sure they know Christ. so where is the line?