How to know you love someone

What it takes to love someone. To love someone is to accept them as they are? Do we need this to love someone?
You act with a desire to constantly share goodness with a person. You want him to be happy, you do your best to make him happy. You don't be selfish. You put a lot of effort into his happiness. When you're sad, you're sad. You will have mistakes, you minimize your mistakes so as not to upset him.