Disingenuous to release guides for people getting married? (6)
I believe the answer is:
unions
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for unions that I've seen before include "Matrimonies" , "Employee's organisations" , "Workers' associations" , "Undoes a knot" , "Marriages or workers' organisations" .)