Someone's been listening to Boku no Uchuu ni Kimi ga Iru too much. "Kimi no shiawase" means "your happiness". I own not the song nor the singer.

Kimi no Shiawase

If I may have one wish
Kimi no shiawase
I want your happiness
Even if it's not with me
Kimi no shiawase
I want your happiness

A long time ago
I believed we were
Meant to be

But it's not so
You are not her
And I'm not he

I can only protect you
Nothing more
I can't cause your delight

I can only direct you
From a distant shore
And dream of you at night

But I can always hope for
Kimi no shiawase
I want your happiness
I will always pray for
Kimi no shiawase
I want your happiness

I won't be the one to cause
Kimi no shiawase
I want your happiness
But that won't stop me from hoping he will
Kimi no shiawase
I want your happiness

If it can't be me
Kimi no shiawase
I want your happiness
Then it must be him
Kimi no shiawase
I want your happiness

So, crimson-girl, never forget
Kimi no shiawase
I want your happiness
It must be so
Kimi no shiawase
I want your happiness

You must be happy

Owari