Hi, Elizabeth If only 认识 and 知道 two words. Their meaning are different. learn and see(understand).But In these case. They are same meaning. you know affection(love). In Chinese way to say that: 我终于知道(认识)爱是什么东西。It is weird if say我认识爱，或者知道爱。Then they would hesitate what do you learn about affection? But you can ask 你认识爱吗？Asking is coherent. 认识 generally using with people, places,interpersonal, skills,knowledge. 知道 generally using in knowledge, events, and answer I see.... Good Luck!

认识 is used to + somebody, means we are know each other. ( sometime, 认识+ sth. means recognize... for example, I'm sorry that I 认识到it's my fault ) 知道 is used to + somebody or sth. means mastery or know. + somebody means I know him, but maybe he dosen't know me. + sth. means I've heard it or I know this ( news or knowledge....)

hi,Elizabeth, actually, we never say "认识爱"and“知道爱”。 maybe you can say "最后，我终于知道了什么是真爱"，to express"finally i know what real love is " or you also can say" 最后，我终于学会了如何去爱"， to express "finally, i know how to love a person " if you say"最后，我认识爱"or“最后我知道爱”，both sentence are so odd.

如果单从这句话来说..我觉得应该用了解爱. 认识和记得这俩个词形容爱 很难形容的很恰当

我们一般说知道爱，但是你可以说“我认识这个人”