To obtain this achievement you need to get the ending that results in you romancing Akiko. To do that you need to follow these choices exactly. Feel free to skip through the dialogue in between to speed things along.
-Only abit
-I have no idea
-Disagree
-Fight back
-Stay in class
-Stay silent
-Ask what happen to Hikaru
-No
-I want to prove I am better then you
-Because swimming is important to me
-Resist
-We're very close
-Break up with Arata
-Admit the truth
-Challenge Rika