How did Hashem answer Moshe's query?
Ramban #1: Hashem informed Moshe that if he did not want to be cured 1 that was fine with Him, and that, as for the problem with a person with 'uncircumcised lips' appearing before Pharaoh, He would see to it that whenever Moshe spoke in His Name, He would personally place the words in his mouth, so that they came out eloquently.
Ramban #2: Refer to 6:12:1:1.
What is "v'Horeisicha"?
Hadar Zekenim (1): It is an expression of Herayon (pregnancy); it will be like a new creation (Moshe's ability to speak).
Hadar Zekenim (2): It is an expression of shooting arrows (Hashem will put words in Moshe's mouth).