Mitsuba is cocky, foul-mouthed, and very confident in himself, particularly his looks, and often brags about how cute he is. He has a tendency to call people by rude nicknames, and isn't afraid to throw insults. He knows how to get on people's good sides, and sometimes acts nice to someone if he needs to get on their good side. He has also been shown to be quick to cry, especially in threatening situations. 

Here is his voice as reference: https://www.youtube.com/watch?v=Dis_-HHdLYw&list=PLVxqNewsBC1CVnM_r0H5USDaTMWLeytlf&index=8  feel free to aim for a bit higher pitch that what he sounds like in the dub!