After his apartment burning to the ground and almost being killed by a falling metal object, Ohmura Takeshi is ready for the afterlife. Luckily, a beautiful angel appears to heal his wounds and inform him that if he stays with her, no harm will come to him. The catch? His long-lost deadbeat dad has passed along a curse: he will experience nothing but sadness in his life. Now, after changing to a human to maintain close contact, Elle will stop at nothing to make sure that a bit of happiness comes into Takeshi's life, but not before first learning how to be a human!
A year after their spaceship crash-landed on Earth, the alien species known as 'DearS' have been accepted into the Japanese citizenry. They are adored by many fan groups and trusted by most humans - with the exception of Takeya Ikuhara. Kind-hearted but resistant to change and skeptical of the DearS' seemingly-friendly behavior, Takeya tries to have as little to do with them as possible. But after he saves a girl from an incoming truck, and she turns out to be a DearS, Takeya ends up being far more involved with them than he could have ever imagined.
Somehow DearS reminded me of Happy World!, probably because of similar story and characters. If you read Happy World! and you're looking fora similar manga, than you probably should give DearS a try.
A guy who has terrible luck comes across a non-human girl who is set on protecting him from said bad luck. The thing is, the girl in question proves herself to be more trouble than help. Kitsune no Yomeiri is probably the better one among those two, but if you find the plot interesting you could give both a try.