You sound exactly like my father. He's said the same to the three guys who married my three sisters. He is a jovial, peaceful man. Far and away more peaceful than I.
But when he talks in full sincerity, no one doubts him. And I don't doubt you.
Thank you and welcome to the life side.
Your father sounds like a good man. I'd be willing to bet that no man ever even tried to take advantage of your sisters.