Trust: What is trust? I think it's a combination of reliability affection and respect. Some would say that reliability is the only neccesary component but I disagree, at least when it comes to interpersonal relationships (If I say that I trust a brand of antifreeze I don't need much affection towards it) I mean if someone's behavior is predictable but offensive would you say that you trust them? I don't think I would. Maybe it's because one doesn't attribute positive traits like reliability to people you don't like, but I think that it goes a little deeper than that. See trust implies, I think, that whatever behavior the person operates with what are, by your lights, generally good intentions or at least not bad ones. That's where the respect comes in. To trust somebody you have to believe that the choices they make and the actions they take are both rational and motivated by a desire to achieve something worthwhile. It doesn't have to be something you think is GOOD but you have to at least understand how it could be seen as good.
Affection is the hardest aspect of trust to talk about. It doesn't seem inherent in the equation like reliability and respect might, after all we've all heard lines like "I don't like him, but we can trust him" etc. Ultimatly I think it comes down to comfort level. To REALLY trust somebody you have to feel comfortable around them, and I think comfort is part and parcel of affection (perhaps you can have affection without comfort but is the opposite really possible?) You don't need to have a STRONG like of the person, just a general feeling of "Hey he's a pretty good guy, I like him" or something vague like that. Your general disposition has to be positive for you to really trust them.
Okay you say, that's nice, but what exactly does it have to do with love? Well I think trust is neccesary for love and is perhaps THE fundemental component. Trusting somebody means that you can rely on them, you respect them, and you have affection towards them. Reliability is important because if you're planning on making this person the rock in stormy waters on which your life is built you need to know it won't sink or float away. Respect is important because it allows one to take the other party's point of view rather than dismissing them as "overemotional" or "insensative". Affection doesn't really need to be explained because people often mistake raw affection for love (affection is a large part of love, the main part of the raw emotional ingredient, but I think love has a cognitive aspect too.) Trust combines three important traits for any sort of romantic relationship and wraps them up with some additional implications.
Intimacy is the sharing of private information/merging of experience and worlds. When you are intimate with someone it means that you have a connection to them on a private level. They know things about you that few others do and you reveal information to them that you don't neccesarily want them to know just because of the bond knowing eachother's secrets creates. Likewise when you are in an intimate relationship your perception of events/people around you is colored by your partner. You understand their thought patterns and personality well enough to automatically think of what their response to a joke or opinion towards a piece of art might be. Intimacy is connection on a very personal level.
Now intimacy and trust aren't the only ingredients for love but I singled them out because I think they are the hardest to achieve. The fact of the matter is that it's DIFFICULT to find someone who is reliable and respectable (many reliable people tend to be easily pushed around, which is WHY they are so reliable) and it's tough to find someone you can feel comfortable being intimate with. Affection is pretty easy, all it requires is that you accentuate the positive. Trust and intimacy force you to confront and deal with potential negatives...I think they are usually the last pieces to fall into place during a budding relationship but they are essential.
So what is love then? Well I'm very tired and this entry is not entirely coherent but basically I concieve of love as a combination of a lot of things. Trust, Intimacy, Affection, Attraction, Understanding, Exploration (even though people in love understand eachother they are not bored by each other, there's always some other aspect to probe and explore) and mutual need. A lover is someone who makes you feel better by their mere existance let alone presence. They provide shelter from the storm and safekeeping for your secrets. They give both physical pleasure and intellectual stimulation. They are satisfying to please and painful to hurt. I could say more but you get the gist. Lastly a lover must be unique, she must be special and neccesary to your continued happiness. She can't fill a void that another could fill just as easily.
Or so I think...I really wouldn't know.