If you lie about this, you will never be trusted with anything. This is just plain trickery and there is no way to deny it. It is much better to tell the truth up front and the shadchan should explain the financial situation from the start. You can’t just pull things like this on a young girl and her family and not expect a reaction. And you can’t lie about something like this to a wife or a daughter-in-law for years and not expect this to have huge repercussions.
Marriage is based on honesty and trust. Mother-in-law/dil relationships are based on honesty and trust. Doing such a thing absolutely turns the tables on the foundation of trust and honesty. How can you trust someone who lied to you from day one? What else have they lied to you about? What this says is “you are not important to me therefore I can lie to you, if you were important to me I would tell you the truth because I would be afraid to start off on the wrong foot or do anything to ruin our relationship.”.