You just simply go out of the map, you see a ! mark on the map. Simply go there, duel, win
the opponent, then you shall get 2 hearts and up so on and so on,....

Something must be wrong here because I already did that and it's still stuck at one; is it
just because of the partner I chose or is it a glitch?

I DID THAT TO BUT NONTHING HAPPEND

nurds try to get friends

i think you get 2 hearts once you have done like 20 duels or so on but only if your first
heart is maxed out i got 2 hearts like 10 days after dark magician girl duel

its not a glitch or something is natural when you fill 1 heart an event happens, then
after that event you will do what you did to the earlier heart filling to get another
one...

you have to buy sandwiches and give them to your partner or you could win a hard duel.

bye the golden egg

All u do is u will stay at one but u will get more hearts all u have to do is buy him a
sandwich keep doing that or duel alone and then u will get more hearts trust me i have 5
hearts from doing that

I did that but no hearts so you all are a sick freak nerds

I won more 200 times and gave sandwiches and i don't have any missions to do, i don't
understand this game wtf should i do