How do you know if you love someone ?

Many Factors: Love is complicated and should include multiple components such as attraction and/or interest in areas such as physical, emotional, mental, and spiritual. Spending time in each of these areas is very important so try and not let one become more important than the others or you could be mislead (for example physical or sexual activities can falsely elevate the thought of being "in love").

EXPERIENCE: After you love several people (and pets maybe) you'll will get the sense of it. Sexual attraction without love fades with time. Love what you see, not what you hope for in the future. Potential is not more than that. He should be nice, honest and reliable. If not you have a lot to learn.