For example, this is a story I told her, a story that she never forget (she told me):
Yuuichi is the main character of the story, he's an orphanage, who were adopted by someone. In his young days, he work at a massage parlour. When he grew up, he quit that job completely, attend college and make a living by becoming a part-time tutor for highschooler.
Then he met Risa, his new neighbour, who recently lost her older sister. He helped Risa to become known to the new town. In exchange, she helped him with the cooking and part of the house chore. Eventually, they become closed friend.
One day, Risa witness a dog being tortured. Angry, she confronted the owner, and learn that the owner would be willing to sell the said dog for a huge amount of money (in million yen). Being desperate, she asked if Yuuichi could know how to earn such number in a mere day. In reply, Yuuichi say the only way would be to sell her body away, though, he recommend her to think through. Having no choice left, Risa reply, and was stunned to know that Yuuichi would be 'buying' her. His conditions were that until Risa pay back the amount of money, Risa can no longer sell it. Joy and sad at the same time, Risa accept the money, and promise Yuuichi that one day, she will pay it back. With that, both of them proceed to meet the owner, and buy back the dog.
Eventually, after that they become even closer to each other, and of course. We all know the final ending of the story: they married and live together happily.
I cut the ero part for you but yes, typical eroge story :x