You could say "Eres mi rosita linda"
rosa
You can say "Eres bonita".
bonita
You can say "Ella es bonita".
Whether a name is pretty or not is a matter of personal opinion. For any name, some will say it is pretty and some will say it is not.
mujer bonita
Rosado/a. de color rosa.
Rosa hermosa or Rosa Bella
Gracias por la Rosa
There is no direct translation for "pretty please". Simply say "Por Favor" (please).
You can say "Ella es muy bonita".
You would say "guapa pero gorda".