Then Manoah entreated the Lord
Josephus F12 makes the woman to entreat the Lord; but the text is clear for it that it was Manoah that prayed:
and said, O my Lord, let the man of God which thou didst send unto us;
he believed that the man that came to his wife was a man of God, and that he was of his sending; nor was he incredulous of the message he brought, as appears by what follows:
and teach us what we shall do unto the child that shall be born;
he believed there would be a child born, and he knew what was to be done to a Nazarite in common, according to the law of God respecting such, and the angel had mentioned somewhat to the woman; yet this being an extraordinary case, a Nazarite from his birth to his death, he was desirous of knowing what was further to be done; or if there was any thing more special and particular to be observed concerning him; which showed his readiness and cheerfulness to obey the will of God in all things.