Does the saying "What is built upon falsehood is false" apply to an engagement that took place via social media and was rejected by the father, and what is the correct course of action to complete the marriage in a permissible way?

Most interactions between young men and women via social media are a gateway to evil and corruption. However, their occurrence does not preclude marriage. Objecting to marriage in such cases with the saying: "What is built upon falsehood is falsehood" is incorrect, as marriage is built upon a valid, religiously-sound contract. There is no impediment for the young man and woman to marry after an unlawful interaction, keeping in mind that the suitor is a stranger to the fiancée before the legal contract. The young man is advised to discuss the matter with his father to convince him of the marriage.