the present is all there IS, sure the past was and the future will be but all that is is now - so say something isn't true because it doesn't last forever (or more sensibly, until the death of someone in the equation) doesn't make it any less real. Most things have a beginning and an end - and in between those points and as time goes by, things are always changing. Our perception of change relies as equally on our perception of time as our perception of time relies on our perception of change.
I know I'm rambling about some pretty abstract stuff here but it confuses me why so many people seem to treat "true" as meaning eternal or something like that. If your definition of friendship or love is something elaborate, impossible or highly unlikely, then it's non-existence is a logical thing to believe in only because of that definition that you're using.
Whether you're talking about platonic love or romantic love, I think of each as having two senses: the first being the emotion, the second being the nature of the emotional bond between two people in terms of the emotion they feel for each other as well as the interaction between them. So yes, I think that exists, hell I even think I know that exists. How does adding "true" before it change anything? True as in not fake? Not imaginary? Well, yeah, I already said I think I know it exists, obviously I meant I think it REALLY DOES EXIST. If by "true love" we aren't simply using our definitions of "true" and "love" in combination, but it's some kind of expression with a meaning that goes beyond the combined meaning of those two individual words, it depends wtf we mean when we use that expression.
Here's my answer to some specific meanings that I've heard:
~ Some people think of it as meaning "forever and for always" or something like that and in that context it seems few people pay attention to the fact that there's always a beginning, before which it wasn't there - but if we ignore that and don't get into a religious/philosophical debate on things like life after death, let's say "forever" means until death. In this case, then yes, I think there are people who have fallen in love and remained so throughout their life. I can't know this since I haven't lived the life of any such person and someone who appears to have had that happen may simply appear so to the rest of us, we don't know, we're not them. What we do know is that there are plenty of people who don't have it like that and that we can't know there aren't people who do.
~ Some people think of it as having something to do with everyone having one soul mate, only one other person in the world that they are romantically compatible with in order to experience "true love" - This sense, I do not believe in, because I see no reason to. I see reason to want to believe that, I see reason to believe it would be advantageous to believe that, and as someone who believes in evolution, I see why it makes biological sense (as a species is supposedly inclined to mate for life) for us to have evolved to feel that way... but it also makes biological sense to be attracted to the opposite sex and to procreate and I see no reason to believe that 1 and ONLY 1 out of 6,775,235,700ish people on this planet are suitable to be my life long mate and that there aren't ten, twenty, a hundred, or tens of thousands who are equally fit to be the one for me. Should I find a "perfect fit" it would probably be beneficial to think that they're the ONLY fit and that there is no other but should something happen to make that not work, it would probably be beneficial to think that maybe there IS someone else... but regardless of what benefits may or may not come with thinking this or that, I just don't see any rational explanation for everyone having only one potential soul mate. I believe in having just one of something you may choose to call a soul mate, but that's one of many potential ones and is defined as a soul mate by what happens, not what could happen and certainly not by what doesn't happen.
~ Some people mean unconditional love and as far as any practical sense of this goes, then yes, of course I think unconditional love exists, we see it everywhere. If you mean in the absolute sense, then no, it doesn't, just like there's no absolute knowledge in science but we still have "scientific knowledge" that we can functionally treat like absolute knowledge because despite the fact everything is uncertain, some things are so damn near certain that we can take them for granted and act like we know, because we pretty much do know. Likewise, unconditional love, in the practical sense, would mean love that persists regardless of the loved ones actions or qualities. Just like nothing is absolutely certain in science, there's no absolute unconditional love in that in some bizarre but possible sequence of events, the loved one could drug or cause brain damage to the otherwise unconditionally loving one causing them to be neurologically incapable of feeling love, in which case the loved one will have effectively prevented someone from loving them... so everything is conditional and nothing is absolute but in practical terms that are not impossibly strict, unconditional love absolutely exists.
~ To those who define true friendship and true love as being so intense that the relationship or emotion in question will persist until death, I would respond that the intensity is not the sole factor in how long it will persist and that everything is subject to circumstance. Like I said, I'm pretty sure (but not totally sure) that life long friendship and life long love can happen - but if you think that friendship or love that wains in intensity or ceases to exist entirely is an absolute indication of what it was when was at it's finest, then I disagree. We got where we are now from where we once were and we'll go where we go from where we are now but unless you're all knowing, you can't define what is now by what lies ahead and you can't define what is now by what once was. We can get clues about the past from the present and we can get clues about the future from the present and past but we can't totally define any one of those from the other. If your definition of the phrase "true love" or "true friendship" has any criteria in temporality, it's subject to that definition. If your definition is subject to no temporal criteria what so ever, well then time is irrelevant now isn't it?
...it truly is mind boggling how much our perceptions of reality are based in abstract semantics and subject to the weaknesses of language and even more so, just the way we use it.
I'm going to post this without proof reading it and risk looking insane, then laugh at myself if I do. Time, logic and language are a recipe for disaster with me.