Here's a pretty good indication that you're in love, and it's surprisingly painful and yet very common. And it all begins with a nagging doubt about whether or not they truly love you back.

Do they love you in the same way that you love them? Can the intensity of your feelings be returned by someone whose heart you will never fully understand or know? Isn't this one of the most common romantic insecurities, saying I'm not sure if you really love me.

It's also why the French psychoanalyst Lacan said that the most dangerous question any relationship is do you love me? Because even if they say yes, you may begin to suspect that they are only saying it to make you happy.

Now, the poet WH Auden has a lovely line about this: "If equal affection cannot be, let the more loving one be me." This should be your response; do not call their love into question.

Be confident and sure of your love for them.