:)
[name_f]Do[/name_f] you have more info about this? I would assume that the nickname for [name_m]Manuel[/name_m] would be [name_m]Manu[/name_m], and I can’t find anyone named Sanu when looking at Romanian sources. I’d love for it to be true though because it’s really cute!
This one can also be related to [name_m]Hermes[/name_m]! (: It’s the Greek form of [name_f]Hermia[/name_f], like the character from Shakespeare’s A Midsummer Night’s [name_f]Dream[/name_f]! Really pretty 
As far as I know this is just a surname, not a surname name, but let me know if I’m mistaken!