Brenda,
The marriages took place in the Farnham registration district (which covered places in both Surrey and Hampshire), not necessarily Farnham itself. I'm afraid this means that it could have taken place in any church of any denomination in any of the following parishes as well as the register offices:
Aldershot, Ash & Normandy, Dockenfield, Frensham, Frimley, Seal (from 1869) Shottermill, Waverley
Are you sure that she married? Perhaps if you give when and where she was born, it may be possible to find her after 1871, especially if she stayed in the same area. Do you have her parents in 1871? Where were they?
Nell