Mattaku, Honto help

Anata wa totemo kawaii mattaku desu you.
Hontou ni watashi wa anata wo koishiku omou desu you.

Are these being used right? They don't look correct to me, but I can't figure out why exactly.

Anata wa totemo kawaii (desu).
Watashi wa hontou ni anata ga suki desu./Watashi wa hontou ni anata wo aishiteimasu.

The sentence final particle is "yo".
"Omou" is a verb, so the copula "desu" is not needed.
"Koishiku omou" is not usually used when directly saying to the one the speaker loves.