Definitely, not defiantly.

I agree with Randy, you probably mean definitely. However, just in case you mean "defiantly", here are two sentences and their meanings: "I'm definitely interested in having a class with him." I am absolutely, 100% certain that I want to have a class with him. There is no doubt in my mind. "I'm defiantly interested in having a class with him." Even though he, or other people, absolutely do not want me to have a class with him, I absolutely do want to have a class with him. I will do everything in my power to have the class with him, even though everyone is trying to stop me. Finally, notice my sentences use "in" not "into". You are "interested in" something not "interested into" something.

thank you Allen. I didn't know it should be " in" instead of " into" until you pointed it out .

it's from an email I got . what a stupid mistake.

thank you guys. I confirmed with someone, she meant definitely.