Byakya and Hisana is a great love story that tells of how the noblest of of noble, the head of the Kuchiki clan, defied his clan and married a lowly peasant girl from Rykongai and made her into a Hime of Seireitei! But alas, it is tragic love story and she died within five years of marrying Lord Kuchiki Byakuya!
Hisana's dying wish was for Byakuya was that he find her sister Rukia. The sister she abandoned out of necessity but an act she forever regretted and tried to amend by finding her but could not before her time was up. As fortune would have it. Byakuya found his sister-in-law just a year after his wife died and he adopted her into the Kuchiki family and they all lived happily ever after!
In other words, sure there is romance in Bleach!