try this one
Kono Minikuku mo Utsukushii Sekai - interesting story about life and the earth wrapped around the relationship of two people, a bit ecchi but only in the first few eps.
Erementar Gerad
The relationship between the couple is obvious and absolute as they go on an adventure while discovering their care for each other.
Karin- it's pretty good, very solid relationship that develops.
Shingetsutan Tsukihime- good anime very touching, also play the game which has been fully translated.
Utawarerumono- A bit more action then romance, but the relationship between the couple is sweet and touching, the ending was extremely good too.
Tsukuyomi: Moon Phase- This one had me confused as to whether the relationship was romantic or familial, but there was definitely chemistry between the two!