Shall not doubt in his heart (μη διακριθη εν τη καρδια αυτου). First aorist passive subjunctive with ος αν. The verb means a divided judgment (δια from δυο, two, and κρινω, to judge). Wavering doubt. Not a single act of doubt (διακριθη), but continued faith (πιστευη).

Cometh to pass (γινετα). Futuristic present middle indicative.