Sometimes, even when there are sources for a relationship, these sources can be questionable or leave some room to interpretation (e.g. misspellings, dates that do not quite match, etc.), so even if a relationship is likely, it's not always 100% confirmed.
It would be convenient to have a way to mark a relationship as "likely, but not entirely sure". That could be either towards a husband/wife, and towards one's children.
In the tree view, that uncertain relationship could also be shown with a different line color, or maybe with a question mark next to it.
Right now, as a workaround, I just use question marks in the person's name to indicate that uncertainty.
