@FredFriendly:
Kitazawa 
admits to liking Keisuke which is more than Maiko has ever done, she's                                                                                                       
shown to care for him on multiple occasions, and is on the whole a more agreeable                                                                                                      
person than Maiko, it'd be hard to not assume the worst.
She also has no reason not to trust Kaede. If she thought about things a little                                                                                                       
more she might find it suspicious that Keisuke, who has insofar never shown                                                                                                           
interest in anything other than baseball, is suddenly aiming at his club manager.                                                                                                     
She might also question the fact that Kaede, who she knows is interested in her,                                                                                                      
is the one to tell her that. Though I do not think that she's capable of figuring                                                                                                     
that out right now.                                                                                                                                                                   
                                                                                                                                                                                      
Referring to the festival, it was Kaede who invited Maiko and not the other way                                                                                                       
round. Yes, she could rebuff Kaede, be more proactive, and invite Keisuke, yet                                                                                                        
this too doesn't seem likely at this point. Maiko has seen that Keisuke goes to                                                                                                       
the batting centre with Kitazawa on his days off, so the assumption that he would                                                                                                     
be training is not an unreasonable one either. Indeed, I find it impressive that                                                                                                      
she continues to believe that Keisuke is training and not going out with Kitazawa.                                                                                                    
                                                                                                                                                                                      
I do think Maiko is responsible for her situation in many ways, her relative                                                                                                          
inaction in the long-term and her outburst at the end of this chapter in the                                                                                                          
short-term. Yet I think that this realisation is probably the best thing that                                                                                                         
could happen to her at this point. It gives her the opportunity to realise that                                                                                                       
Keisuke cares for her in his own fashion and that she needs to either step up her                                                                                                     
game or question whether she's the right person to be beside him.                                                                                                                     
There is a chance to end this gracefully, though I doubt that will be the case.                                                                                                       
Given your foreknowledge of the number of chapters, I expect that you've read                                                                                                         
ahead and that Maiko and Keisuke are exonerated without either one learning what                                                                                                      
they did wrong.