How do you know if it's love?

Is it love when he or she says I love you? Is it love when he or she gets a real nice gift? Is it love when he or she whole you all night? Is it love when he or she kisses you for hours? Is it love when he or she looks into their eyes? Is it love when he or she makes love to you for hours? Is it love when he or she says I do? Is it love when he or she has a passionate dream? So I ask you again how do you know if it's love?