When the person you’re in a relationship with is less than truthful with you about money, that’s certainly a major red flag. Maybe they’re dishonest about everything in general, or maybe their lack of truthfulness is just related to money. In either case, this type of behavior is concerning in a partner.
There are various ways a person can lie about their finances. For example, they may be dishonest about their spending habits, either claiming things cost less than they paid or even hiding purchases to keep their partner from finding out what they have bought. They may also lie about how much debt they have, claiming to owe little or no money when the opposite is true.
Financial lies can also be about earnings. A person may pretend to make more money than they actually earn, a lie that may contribute to additional dishonesty about spending. Or, they may claim to earn less than they do, as a way to manipulatively guilt you into contributing more than your fair share without expecting them to pay more.