Japanese phrase to express the feeling of love

Here are some phrases in Japanese to express his love to someone.
I like you: kimi / anata no koto ga suki da; suki da
I like you: Daisuki da
Be my boyfriend: tsukiatte kudasai
I love you: aishiteru (yo)
Do you already have a boyfriend?: Kareshi ga iru no?
Do you already have a girlfriend?: Kanojo ga iru no?
What you've been going out with someone?: Dareka to tsukiatteru no?
I promise I will membahagiakanmu! : Ni zettai shiawase ni suru kara!
vocabulary:
Aisuru: loved
Suki: like
Daisuki: loved
Tsukiau: courtship
Kareshi: boyfriend
Kanojo: girlfriend, she (female)
Koibito: girlfriend (regardless of gender, neutral)
Iru: None (for living things), has
Dare: Who
Dareka: someone
Daremo: anyone
Zettai: continue, always
Shiawase: happy, fortunate
Shiawase ni suru: happy, make happy