You might need to 'cope' one end of the rope.
One end is cut at 90 degrees, and then instaled. The 2nd end is 'coped' around the installed 1st end. (All this assuming you're talking about an INSIDE corner.)
For outside corners, you cut an inside-angled 45 on BOTH ends. This way, they meet at 90 degrees.
My best to ya and hope this helps.
Jay J -Moderator
PS: In either 'situation', the inside of the rope isn't seen.