I think that love (noun) refers to the condition in which one’s happiness depends on another’s.
And therefore to love (verb) must mean to act in a manner consistent with this condition prevailing.
If we adopt these as our definitions, then it becomes obvious, upon cursory examination, that we can never accurately describe actual “love” (either the noun or the verb) as either universal or unconditional for long.
For example, unrequited love would tend to consume, either its host, or its host’s willingness to continue entertaining it; for it entails costs with certainty, but holds out no sure promise of benefits, and would be easy to take advantage of.
But reciprocal love may prove (under some conditions) sustainable or even (under others) productive.
Curt Doolittle made a status the other day, or perhaps a comment, wherein he opined that the statement “I love you” must resolve operationally to something like “I promise that if you test the hypothesis that ‘I love you’ you will not find it untrue.”
So we can resolve this still further to say that “I love you” means “I promise that if you test the hypothesis that my happiness depends on your own against my actions, you will not find it untrue.”