Those effects are probably due to the ingredient β-phenylethylamine.

β-phenylethylamine is often referred to as the “love drug” due to its aid in releasing dopamine and serotonin in the brain, resulting in good feelings, much like the feelings felt when falling in love.

β-phenylethylamine is actually the ingredient in chocolate that makes you feel good. It is also the reason why some people say eating chocolate can help you fall in love.