What is love according to Hinduism? What is marriage according to Hinduism?
What do scriptures say about them?
I will answer on the love part. The Narada Bhakti Sutras or the aphorisms of love talk at great length about Bhakti or divine love. I am sharing a couple of Shlokas here with the meaning:
|| Yat Prapya Na Kinchid Vanchati, Na Shochati, Na Dweshti, Na Ramate, Notsahi Bhavati ||
"Having attained that, there is no more craving, no desires, there is no sadness, you do not hate anything, nothing else seems more rejoicing. (you are not over excited about anything)."
||Yat Gyatva Matto Bhavati, Stabdho Bhavati, Atmaramo Bhavati||
"Knowing which you become intoxicated, so still deep within you; you are reposing in the SELF."