Formal:
* 御清め (o-kiyome): This literally means "purification" and is used in a religious context to bless something or someone.
* ご加護 (go kago): This means "protection" and is often used to wish someone good fortune or protection.
Informal:
* 神様 (kamisama): This means "god" and can be used in a similar way to "bless you" after someone sneezes.
* お祈り (o-inori): This means "prayer" and can be used to express a wish for someone's well-being.
* 頑張れ (ganbare): This means "do your best" and can be used to encourage someone and wish them luck.
Specific situations:
* Bless you! after a sneeze: くしゃみをした時に言う言葉 (kushami wo shita toki ni iu kotoba). You can use "お大事に (o-daiji ni)" which means "take care of yourself" or "神様 (kamisama)".
* Bless your heart: お優しいですね (o-yasashī desu ne) which means "you're so kind".
The best way to say "bless" in Japanese will depend on the specific situation.
For example, if you are praying for someone's health, you would use "お祈り (o-inori)". If you are encouraging someone, you would use "頑張れ (ganbare)".