How does victor deal with the birth of the monster?

It was not specified, but I will assume from context that you are referring to the story 'Frankenstein' by Mary Shelly. Victor was horrified when he saw his creation.

Explanation:

He had invited his professor to his house to see his 'experiment', he acted in a way that would suggest excitement (which would hint he thought he thought it was a great idea). His professor is horrified, and after he brings his creation to life, the creature kills Victor's professor out of fear. Seeing that he has created a murderer, Victor is horrified, deeply regretting his decision. This is particularly shown when he immediately flees (it has been a while since I've read this, but I believe he had fled to Switzerland) with his wife (or fiance, I don't remember for sure which but I believe she was his wife) and friend. Victor never recovers from the horror (and I assume shame) as he defies the monster when he later returns to Victor.

If you need more help or don't understand something in my answer, feel free to comment or message me for further explanation.