well, did you debug your pokemon's ev past 255? Because pokemon can only have ev total of 510(255 max for one stat). I once debugged 255 for all stats and then evs became -999.
So basically, in ch3 , in the manor's dining room , if you talk to marianette, there is a small chance that she will say that she hasn't ate and ask for an oran berry(might be any berry idk), if you give it to her you get max relation points