Shall not doubt in his heart (mē diakrithēi en tēi kardiāi autou). First aorist passive subjunctive with hos an. The verb means a divided judgment (dia from duo, two, and krinō, to judge). Wavering doubt. Not a single act of doubt (diakrithēi), but continued faith (pisteuēi).
Cometh to pass (ginetai). Futuristic present middle indicative.