Harvest Moon: Grand Bazaar help?

Okay, so I'm ridiculously confused on this. I'll look into the bookcase(assets) and it shows townspeople's hearts and the whole friendship thing. Well, I'm trying to marry the special bachelor Amir and I'll look at his heart things and his two hearts are orange while Angelo's hearts are red?? I don't know what the difference is between the orange hearts and the red. Why are they different?