"Melva" is supposedly a feminine form of an old Celtic name meaning "chief", although some references sources claim that this name first came into use in the 19th century and was actually derived from the earlier, 18th century, name of "Malvina ", which had been invented by James Macpherson for his Ossianic poems.
Alternately, the name "Melva" can be regarded as another form of the Latin name "Malva", meaning "a mallow", and signifying the color "mauve" which is derived as a dye from the mallow plant.
Buy your lady friend something pretty in the shade of mauve, and present it to her as a gift. Then tell her how that color is connected to her name. She'll not only be charmed by the gift, but also by the fact that you took the trouble to find out something about her name. :)