[bas_I_am]

Let's first use proper english,

The clause "I have a belief that..." is considered poor grammar. This usage indicates the verb is "to have" and is called "passive construct" as it corrupts the conveyance of the subject's action-"to believe". Other common examples include statements of the sort "I made/took a decision" (I decided), "they took a vacation" (they vacationed) etc...

Using your example of an infant, it doesn't apply... has the infant considered the God concept? No... but you have... do you believe or do you not believe? Two states... you are in one or the other. Now that I think about it... the infant does not believe in God.

I believe in God... am I without doubt? At times, no. As a matter of fact, sometimes I have great doubt.