If I understand a sentence's meaning but I don't understand why it means what it means, is that ok? For example, in this image, I was able to understand that the girl wants Sakura to wear a strange costume. Though I got the meaning, I don't know why the volitional form was used. Should I try to figure out these kinds of details, or can I be content with the fact that I got the sentence's meaning?
Thank you for your time.