It could be that she's trying to hide her true feelings or protect someone. Sometimes silence can be a way to cope with a complex situation in the comic world.
Maybe she's just in shock or doesn't know how to express what's really going on.
Well, it's a matter of personal preference. Some people just don't enjoy the format or style of novels and that's okay.
Perhaps there's a risk or something she's uncomfortable with. That's why the girl in the cartoon says no.
Maybe she doesn't like what's being offered or doesn't agree with the situation.
Maybe she's really fond of that doll and wants to express her love for it.
Maybe she doesn't like what's being offered or doesn't want to do something in the cartoon scene.
Maybe she's leaving for some reason. Could be she's done with what she was doing or has to go to another place.
The girl might be saying shhh in the cartoon because there's a surprise coming up and she doesn't want it spoiled. Or perhaps there's a test going on and she's trying to maintain silence.
The cartoon girl might be saying sorry because she wasn't nice to a friend or because she failed to do something she was supposed to do.
Maybe she's being friendly and wants to start a conversation.