Esta muchacha means ''This girl'' but I think it is a bit more informal.
The meaning of that line is "this girl"
It means 'That Girl'
muchacho
mu??t?at???/
noun
noun: muchacha
1.
(in Spanish-speaking countries) a young man (or woman).
a male (or female) servant
"This girl"
What does esta muchacha mean in Spanish ?