月が綺麗ですね | tsuki ga kirei desu ne translates to "The moon is beautiful, isn't it?" This phrase is a more poetic way of saying I love you.
When I first got to know about this I was shook.
In Japanese suki dayo 好き だよmeans I love you.
And tsuki 月means moon, but they're pronounced almost the same so maybe that's the connection.