Here are some examples which crossed my mind:
I enjoyed the love story of Eureka and Renton (spoilers in the video) in Eureka Seven. Even if it dragged out a bit, I was impressed by how well they developed the romance over the episodes and how ultimately had such a satisfying ending despite all the hardships they had to go through to find the road to acceptance. :)
Then there's the destructive romance of Johnny and Gilda from Gilda with this memorable exchange which the whole movie has been setting up. Great stuff from Glenn Ford and Rita Hayworth, and the film is definitely worth checking out for any fan of romance or film noir. :love: