If you are talking and starts with "I know no one" and then you finish the sentence, it won't be wrong, but it is better to say "I don't know anybody who could do it" if you can.

Hi Izabela, The first one is correct but it sounds more formal. If you are using it in a formal setting, then it's great. If you are speaking in an informal setting, I would use the second option.

Hello Izabela! I hope you are fine. I'm a TEFL certified teacher. I would love to help you develop and improve your English communication skills. Don't worry I will help you in every step of the way. Let's be friends! Feel free to message me 🤗

2nd option sounds most natural