Is negotiating the value of the dowry list and paying the agreed-upon amount, given that the agreed-upon amount is less than what is written in the list you signed, considered a sin and a violation of Allah's saying: "And if you wish to replace a wife in place of another, and you have given one of them a Qintar, do not take anything from it. Would you take it by slander and manifest sin?"?

If no mahr (dowry) was specified for the wife, but then the husband agreed to what was written in the list [of belongings], this mahr becomes an established right for the wife. The general principle is that the husband is bound by what he signed in the list of movable assets. However, if the wife, of her own good will, agrees to waive all or part of her right, then there is no blame upon the husband.