This is to be a philosophical argument, so stay away if you are not tired, drunk or otherwise incapacitated. :D

I do not attempt to define True Love in an absolute sense, merely in a way that proves my thesis. However, this is True Love between lovers, as opposed to friends.

My argument is such: True Love demands a lack of physical contact.

My reasoning is as follows:

Strong relationships involve True Love in a total and uncompromising sense, meaning that the two are intertwined in an inseperable fashion. They are, in essence, one and the same thing, as each can only exist alongside the other. Therefore, neither can exist where the other does not.

A major opponent of a strong relationship is Lust. This is because it means the relationship will fall apart as appearance of either party degenerates, or if a more beautiful potential partner comes along. If a relationship is based on Lust alone, either of these will be enough to redirect the driving force of the relationship elsewhere. This means that Lust is, undeniably, the main opponent of a strong relationship and, therefore, True Love.

Lust is defined as the Craving of Sexual Fulfilment, which is caused by physical contact or knowledge of physical appearance (eg. pornography). Therefore, Lust is caused by physical contact or knowledge of physical appearance.

Therefore, as Lust is True Love's main opponent, physical contact or knowledge of physical appearance are also the main opponents of True Love. This means that True Love demands there be no physical contact or even knowledge of physical appearance.

I rest my case. Feel free to comment on my argument or writing style as you see fit.