What are the consequences of informing an adopted girl of her true lineage after twenty years, and is it obligatory to inform her suitor of this?

The invalid lineage of the girl must be annulled, and she must be attributed to her father if he is known, according to the Almighty's saying: "Call them by [the names of] their fathers; it is more just in the sight of Allah." The girl and the suitor must be informed of the truth of her lineage, because concealing this leads to great legal corruptions related to Mahramiyyah (unmarriageability) and inheritance. The corruptions resulting from informing the girl can be avoided or reduced by gentleness, choosing the appropriate method, and consulting psychological specialists.