Love and Heart by Chitose Kaido (#1)

After a messy breakup, college freshman Yoh Yagisawa returns home only to find she has an unexpected male roommate! Introducing himself as her old childhood friend who moved abroad, handsome Haruma Hirose is back to do a homestay. He's totally hot, super nice and always there when Yoh's in trouble... But could Haruma's timing be a little too perfect? Plus the house next door, where he claims to have lived - didn't family there all commit suicide...?