I'll let God figure that out.
If any gods exist, and any of those existent gods wish for me to know that they exist, I'm sure they can be convincing. This includes the Christian god rather unimaginatively named "God". You've convinced me that you exist just from this question, and you're nowhere near being a god. I'm sure a god could be convincing if it wanted to be.
For me to believe that a god exists, I would have to be convinced that a god exists. I cannot just choose to be convinced.
There are two ways for me to be convinced, either through being convinced by evidence and reason, or just wanting so badly that a god exists that I am convinced that one exists whether it does or not. I'm not in the latter category, so I need some evidence and reason to be convinced.
Now, a god is supposedly super-intelligent and super-powerful, to the extent that it would know precisely what would convince me that it exists and precisely what would fail to convince me that it exists. If a god exists, it has apparently decided to be unconvincing to me, for whatever reason. Just as I have no real control over the fact that I believe you exist, I also have no real control over not being convinced that any gods exist.
Also, Christianity only offers a spoon-fed morality based loosely on the rantings of bronze-age zealots. There is little reason to condone it. If there was a god, I doubt it would think very highly of the Christian version of morality, either. Like I said, gods are supposed to be intelligent.