I know you know how much I love you (This is not correct French)
je vous ai manqué
vous ne savez pas ce que je dis > you don't know what I'm saying
How many brothers do you have?
Do you know (about) that I say? (this is not correct French)
Vous ne savez pas ce que vous parlez.
vous savez que je vous aime or tu sais que je t'aime (use the same pronoun in the sentence) means 'you know I love You'
Je sais que vous le savez.
"you know" in french is whether "tu sais" if it isn't formal or "vous savez" if it is formal.
Translation: (Note, I made some assumptions about missing punctuation) If only you knew how how much I love you. If you knew that you are my everything. Maybe, then you would know exactly how much you mean to me. I love you.
'Parlez vous français ?' or 'est-ce que vous parlez français ?'
'And you know he loves you' is translated as 'et vous savez qu'il vous aime'. If this is supposed to be a question (Do you know he loves you?) then it's translated as 'Savez-vous qu'il vous aime?' 'I know he loves me' is translated as 'Je sais qu'il m'aime'.
"[do] you know who I am?"
Est-ce que vous savez? - savez-vous?
"vous savez que vous m'aimez" means "you know that you love me" in French.
To conjugate "know" in French, you would use the verb "savoir." The conjugation for "savoir" in the present tense is as follows: je sais (I know), tu sais (you know), il/elle/on sait (he/she/one knows), nous savons (we know), vous savez (you know), ils/elles savent (they know).
vous savez faire = you know how to do / you can do
Vous savez ce que je veux dire.