In your reactions with your dog(s), it's important to be the recognized Alpha dog of your pack (i.e., family). Although Bella would like to be the Alpha Dog, she doesn't have the confidence. Chief is the quite, assertive Alpha between the two. I am the Alpha over them. (Does that make Chief, the Beta dog?)
Here are a five characteristics that demonstrate that Chief has dominance in the pack hierarchy over Bella. If you want Alpha status over your dogs, you should be sure to the do the same behaviors.
1) First to go out the door. Some times Bella sneaks in front, but nearly always Chief goes out first. This is an easy way to establish authority. So when you take them out for a walk, go out the door first, making them wait until you have crossed the threshold.
2) First to the water bowl. Bella waits until Chief is through. (Now, I'm not saying you should get down on hands and knees and slurp from the dog bowl, but many experts advise to feed your dogs after the family has eaten.)
3) First to eat. Same as above. Although I feed both dogs in their kennels, Bella will wait until Chief starts eating to eat. And if I don't feed them in their kennels, Chief will ...
4) Help himself to Bella's food. If I leave the door unlocked, he will come right into her cage and take over her food bowl. She always acquiesces. (Again, I'm not suggesting you reach in while they're eating and help herself to a kibble, but if you share a snack, make sure you get first dibs.)
5) Gets his way. While this may not seem fair for one person to always get his/her way, it is in the dog pack. If Chief wants a toy and doesn't just want to play with it with Bella (like a tug), he will command that she gives it up. And if he has one, she will not try to take it away. So when you discipline or train your dog, remember you must and should win. If you say sit, do it until the dog sits - no treat or reward until they obey.
I have found the dogs behave much better for me than the children. Why? Because they know I'm the Alpha and outrank them. If they ever misbehave with the children, I remind them of these steps for them to re-establish their place in the pack hierarchy. The dog pack is not a democracy. There is a King/Queen, the Alpha. Your dogs behavior will the better if you are the Alpha, and if you recognize which dog has dominance if you have more than one.