It is actually really tough to speak about Fluorescence without getting negative non-verbal responses. Because of what society understands, fluorescence is a negative characteristic for a diamond to have, and let me tell you- it is really not!
Fluorescence is a natural phenomenon that is defined by the effect that UV light produces on a diamond. Like your teeth get brighter under UV light, diamonds emit fluorescence. Depending on its intensity, it is referred as being none/absent, faint, or strong- and it only lasts for the period when the diamond is under the ultraviolet light. It really does not affect your stone in any way unless the stone seems hazy under the sun!
There is a large misconception that since strong fluorescence stones are usually less expensive, the stone will be worse. Again, my advice is to actually see it in person and not rely on the paper... It might shine just as clearly as a non-fluorescent diamond. In fact, a diamond with fluorescence and one without fluorescence can't really be distinguished most times!