my sentence is "Getting an A in this class gave me the confidence in taking graduate-level classes."
here do i need to use "the" in front of confidence or do i need to omit it?
Thank you for your reply in advance.
Your sentence is clumsy because of in taking, not because of the. You could say, "Getting an A in this class gave me the confidence to take graduate-level classes." You could also say, "Getting an A in this class gave me confidence to take graduate-level classes." Either way is fine. Using "in" makes "in taking a graduate-level class" a prepositional phrase, which leaves my ear expecting another verb.
Use of the definite article in this case would be preferable. However, this sentence is strange without context. Are you trying to convey that you are currently receiving a grade from the "graduate-level class?" If so, it would be better to say, "It me confidence to continue taking graduate level courses when I received an 'A'."
On the other hand, if the class that is mentioned in your question is not a graduate level course, it is merely a lower level course which gave you confidence you should say, "The 'A' that I received in my course gave me the confidence necessary to take a graduate level course."