Answer:
When first thine earnest eyes with mine are crossed .
And thus, I cannot speak of love, as a good thing of my own
Explanation:
From the the lines When first thine earnest eyes with mine are crossed and And this, I cannot speak of love, as a good thing of my own you will see the geneuiness and preciousness of the love from it.
From the lines we can deduce the quality that render the love valuable and how the writer cherish Love.
Through the lines we can understand how beautiful and wonderful love is cherished and how a person can desire good and wonderful for the other person. It indicate the sincerity and truthfulness of the love to the other person.