Don't assume a verbal engagement isn't an engagement. If it were just a verbal agreement without any tokens, you could pretend nothing happened, but the problem is you gave them a token, and particularly, it's a regal gift.
Isn't that going to cost you dearly?
Imagine them coming to your door with a regal token asking for a marriage contract between the two families, then the Prime Minister's Mansion is truly going to make a joke of itself during the New Year. Not to mention, having proposed to the Duke Dingguo Mansion, if they care, the engagement would just be over.
Even if the engagement isn't off, if the Qingcheng Marquis Mansion starts claiming you tricked them into marriage, it would become a joke discussed over tea and dinner in the whole city. Take as a reference a certain family in the capital where a verbal engagement turned into a citywide laughingstock.
