How does loving somebody actually make them beautiful?

The wording of the question is out of order because it is not simply loving someone that makes them beautiful, it is HOW you love them.

In our culture we have turned love into an emotion, it is about how we feel. This is why people use terms like "fall in love" or "fell out of love" for justification of divorce. I am not saying that love is NOT a feeling, it clearly is, but if that is all that it is then we are doomed. I mean, I love cookies, but sometimes after eating too many, I no longer feel like I love them...I feel like I hate them because they are destroying my manly figure (and giving me the runs).

By using love solely as an emotion, a feeling, we cheapen it, and lessen what it was meant to be.

What is love besides an emotion? It is a choice. Look at how the scriptures relate to love:

[list class="bullet-1"][li]Romans 5:8 but God shows his love for us in that while we were still sinners, Christ died for us. This is a commitment type love, not a feeling type love.[/li]
[li]1 Corinthians 13:4-7 Love is patient and kind; love does not envy or boast; it is not arrogant or rude. It does not insist on its own way; it is not irritable or resentful;  it does not rejoice at wrongdoing, but rejoices with the truth. Love bears all things, believes all things, hopes all things, endures all things. This love is action DOES THINGS.[/li]
[li]1 John 4:19 We love because he first loved us. Why do we love? Because He loved us first.[/li][/list]

I believe God does have emotions toward His people, but His love for us is primarily a love of extending Himself, it is action oriented, and of lasting commitment.

How does loving someone in this way make them beautiful? Because it is a choice to SEE them as beautiful even before they are, it is treating them as beautiful even before they are, and it is a love that gives them beauty even before they ever give back.

Eventually you start to truly SEE them as beautiful, because in your heart, mind, and action, they have become that.