It's a romance and josei webtoon where the protagonist is acused of killing her husband and father, and ends up being taken under the wing of a duke(?) and basically she starts to build her confidence, and eventually stands trial etc. and then decides to do work undercover for the duke as a mysterious figure called Raven and like, I think I last left off when they were about to open a school and just managed to help this widow inherit it. The MC has black hair from what I remember and so does the male lead

This is definitely my favorite, Ebony!

Thank you!!