What does Yo quiero tu muy mucho mean?

"Yo quiero tu muy mucho" is really gibberish. It is a grammatical train wreck that translates to "I want your very much."

The sentence looks like some one took the English Words "I [love/like/care for] you very much" and translated them to Spanish individually. Unfortunately translations don't work that way.

The proper way to say "I [love/like/care for] you very much" is simply "Te quiero mucho" or "Yo te quiero mucho"

You never use the Words muy mucho together in Spanish.