Three kinds: passion/impulse, interest/money, and love/understanding+hard work.
Guess which are the good marriages, the happy, stable, mutually satisfying ones? Not the Bennets’ — despite their early attraction, he comes to despise her foolishness and makes her the butt of his jokes, and she doesn’t understand him. Not the Wickhams’ — it’s all impulse on her side and all interest on his. Not the Collinses’ — they’re like the gender-reversed Bennets, without any teasing. But Jane and Bingley? They’re perfectly suited in temperament and their relationship grows, despite hardship, because of real admiration and respect on both sides. And Lizzy and Darcy, the uber-couple? They have to slay countless personal dragons and climb a nearly endless range of social mountains to get to that crucial final proposal scene, which is the culmination of many months of growing realization of how their differences each actually make the other better.
Honestly. Is this a head-in-the-clouds romance? No way. Austen clearly believed that people could marry because they shared a similar outlook, or because their differences were beautifully complementary, and that either of those scenarios was a fertile ground for genuine love, respect, admiration, and affection if both of them worked their butts off.