std::string and const char *

If I use

const char * str = "Hello";

there is no memory allocation/deallocaton needed in runtime

If I use

std::string str = "Hello";

will be there an allocation via new/malloc inside string class or not? I could find it in assembly, but I am not good at reading it.

If answer is "yes, there will be malloc/new", why? Why can there be only pass through to inner const char pointer inside std::string and do actual memory allocation if I need to edit edit string?