His parents have blessed their relationship too. You love to see it. The pressure to make it real is building up from all around them.
I really like that his parents saw through to the in-practice, real state of their relationship. It may be fake on paper, and in his head, but to outside observers, it looks as real as any real relationship can be.
Good to see Youshin's former ice queen-type-kuudere-looking mom can name a dozen things she likes about her husband, who from outside looks as generic as any typical romcom protagonist if he were younger. But I'm sure he keeps his power level hidden well. Yeah, these two were the protagonists of their own romcom back in the day and no one can convince me otherwise.
The parents of both sides are now involved, and mama Shinobu has even exchanged contacts with Nanami. There is even talk of the two pairs of parents possibly going to meet each other (after the 1-month business trip, perhaps). If there is still any intention of backing out of reality once the one month deadline rolls over, they'll have dug themselves into their graves by all of this acknowledgment from the parents. I'd say their relationship is practically a fait accompli now. All that's left is to acknowledge its reality, at some point.
Bold move from Nanami to declare her intention and ask for permission to visit her boyfriend in his house while his parents are away.