In your opinion what causes christians to believe in Jesus

[Sheldon]

Because definitions are not prescriptive. And it is improper usage of a dictionary to shop around the different senses and give them all equal merit. You are supposed to go and look at the context in which a word is used and be able to infer its meaning. And even if you still care about proper definitions, you need to pull out a Greek concordance and dictionary and research its original usage and meaning, not pull out your merriam-webster.

It isn't shopping around. The word has two different senses. Can you not just state which sense you are talking about? Using them interchangeable is confusing. I recommend the second sense when you're referring to faith in spiritual things and just say 'believe' or 'trust' when you mean the first sense.

To be fair, being unequivocal would have made it more difficult for him to change what he meant later on.