When Neytiri says "I see you",
She looks into your heart, and bathes in the beauty of your soul,
She promises to comfort and protect you, and always be with you,
She sees the beauty of the man you are, and the man you strive to be,
She sees her own beauty, reflected within you
She says, "I choose you!", and binds herself to you.

You do not need to say, "I love you!", when Neytiri says "I see you",
She can already see, that you can see her too.