I would consider one's north node conjuncting another person's Descendant highly significant.
Astrologers generally refer to north node connections in synastry as important. This led me recently into doing some personal research into the north node and chart comparison with some spectacular results.
It seems, firstly, that the north node is almost always strongly aspected by an important planet in a family member's chart (usually a parent), and normally the aspect is a conjunction. For instance, the mother's Sun or ruling planet may conjunct her child's north node.
Therefore, the north node is clearly a family bond.
Consequently, any strong connection between a person's north node and an important planet or the Ascendant/Midheaven in the chart of a person who is not a blood relation must, I think, be viewed as significant and binding. I believe it is an indication that the two people have the potential to be like family to one another. If such a north node connection exits between the charts of a romantic couple, then I would see it as a potential for marriage, thus officially creating that family bond.