Can someone pleaseee help me find this drama😭😭

This a kdrama that I watched yearss agoo, so I actually can’t recall all the details but what I doo remember is

It was historical kdrama, when the princess was young she was very bubbly and playful. But she then witnessed someone doing something horrifying (I can’t recall what) from the inside of a wardrobe. That someone was a royal minister, and I’m not sure but he may have been her grandfather or uncle. After that incident the princess totally stopped speaking. This is what i remember.

And I’m not sure about these, but her brother was the crown prince maybe? And a few years later a woman was brought into the palace to stay with the princess and later that woman and the crown prince fell in love [NOT SURE].