Kareshi Kanojo no Jijou, Kodomo no Omocha Recommendations
both characters were enemy at first, but eventually, they get into a serious relationship
Two strong independent of opposite sexes find their paths crossing and face the trials and tribulations of finding their identity as they come of age. If you want to forget the silly, insecure, typical average girl meeting "unattainable" super models and lame coming of age stories and desire a cast of strong, independent characters with the leads realizing how much they enjoy each other's company, then these two works demand your attention.
Although one manga is set in the childhood years and the other in the high school days, both mangas have the same atmosphere. They may appear to be happy on the outside, but pivotal characters both have problems they're running from. Sana and Yukino end up healing their loved ones hearts.