What are the best methods (questionnaires/tests/etc) to measure ability to love?

So far I see those

1. Light Triad Test (described in Scientific American)

2. Big Five personality traits (OCEAN model) - especially its agreeableness subscale (friendly/compassionate vs. critical/rational)

3. HEXACO model of personality structure - its agreeableness subscale + Honesty-Humility subscale

I realize that "love" is a very broad term, which is poorely determined, but anyway let's give it a try! At least let's try to factor out some components of love (loving person) and try to measure these separate components.

P.S. This question is related, but does not provide any clear tests.