When do "LOVE" exist?

When do "Love" exists? I have seen and watch people when they first meet, he or she says, "I Love You". This got me to do some thinking. Do they say it because it was the right thing to do when he or she is in a relationship or is it because he or she thinks he or she understands what "Love" is?

On the other hand, when we plant a seed in the ground, it would requires some universal measure to water the seed without clogging up. It also requires to be put in a good and rich soil than being in a soil where there are full of weeds around. It requires time and patience to allow the seed to grow.

With this same principle, when we meet someone for the first time, we often asked ourselves, "can I trust this person". The more he or she gets to know each other, he or she will eventually develops respect for who he and she is. Within the same take, how much time does it requires to know if someone really do love you for who you are? Is there a time table? People often say, people experience Love in a different level he or she learns.

In the past, when I was dating with someone, he would often say, "I Love You" and we were only dating for like several weeks. I asked him, "how do you know that you love me"? He stated, "It is because I can feel it". When he asked me "how come I don't say, I love you as much as he does" I told him it because if you look at the nature in life, trees, plants have out weight when harsh weather throws at them and they still stands. But when a relationship often in a verbally fights, he or she runs off.

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I have always felt that if you have studs, nails, play woods, concrete in order to build a house. This same take, should be the same way when building a foundation in a relationship when "respect, trust, communication, and friendship" should be working together. Of course, I have seen people starts with intimacy and may lack trust and communication because he or she did not open it up like it should. Of course, "caring, kind, supportive, passionate, affectionate, warm, considerate" are considered components like branches on trees. The more fruits grows on tree, the more abundant of love grows.

The question here, how much time do you need to know a person before "love exist" knowing that it is there without a doubt? Can he or she loves a person without having those component grows? Or do those components should be able to grow in order to develop love for who he and she is? 

Your thought?