Valerie player perspective:
Grave favored. Slow fireball is the key; can't jump over it, can't C through it, so offense is hard. Have to try to stuff projectile startup with f. A more than is comfortable. You can jump over if you're close enough, but the Grave will probably check with f. A before shooting a cloud so it's rare you get a jump-in that free.
Once you get in, his two reversals make going for mixups rather dangerous, but you can punish them both if you just do retreat Yellow a lot, so you should. Valerie can bamboozle Grave by doing a very deep BBC (will jump over Sword and sometimes Dragonheart).
Air to air he dominates you. If you jump first you can try for AA, but the best thing to hit is S (as it doesn't lose to Grave air S.
His jump-ins are really good, and if you have to use Chromatic Orb to keep him out, you lose Disc pressure but it's worth it just to hit him and keep him off you. You have less health so it's useful to just keep him KD and on the defensive.
Overall though the entire matchup is dictated by the interaction between Grave Hold B and Valerie f. A, and the Grave gameplan is safer.