Oh man, Natsumi's actions really did hurt hee stepmom's confidence with how badly she acted a child. Even now, she hesitates in letting Natsumi marry Makoto, because she fears Takeshi might treat Natsumi badly.
If Takeshi somehow met Natsumi's parents, I'm sure their fears would be relieved. But how the heck are they gonna make that happen without Makoto revealing who he really is to Takeshi?