What do you believe the most important factor in a relationship to be?

Respect

Trust

trust would have to be at the tippy top of that list, indeed.

Can you love and not trust? if so, what do you do next?

Honesty. IMO Honesty helps build trust and respect. Without it you got nothing.

It isn’t love. It’s the little things that you have in common.
My wife and I both don’t smoke, don’t drink much, and don’t socialize a great deal. We both wanted families, and had similar views on marriage and parenthood.

Trust

Integrity. If you have integrity, there will be reason to trust you, and you will be honest and respected.

It’s difficult to pick just one, isn’t it! I strongly suspect that’s because they are all functions of each other, one more thing that makes relattionships the hardest job you’ll ever love. : )

Trust. Without it there is little communication and not enough love.

Honesty integrity authenticity

Another vote for trust.

Honesty. Because like someone else above said, you can’t even start to build trust until you know someone is honest.

@DrasticDreamer wouldn’t you need to trust someone in order for you to be openly honest with them to begin with?

@vocalthoughts No. People have things backwards. Being honest isn’t giving someone your bank account, or the keys to your home. It’s not handing someone a knife and telling them to murder you. Being honest from the start is how you know if you ever want to trust someone.

@DrasticDreamer Hmm. Would you say you’re openly honest at the start of each relationship, sparing no details from partners? If no, why not?.. For me, I’d say honesty and trust go hand in hand. One just outweighs the other depending on how you look at things.

Yes, now. I wasn’t, always, which is partly why I’m such an advocate now. The reason I spare no details anymore is because I really don’t see the point of not being honest. Someone is trying to get to know me, right? How, if I’m not honest, will that ever happen? Honesty is how you truly get to know someone, and how you learn whether or not someone is trust worthy.

What else, if not one’s honesty, is what makes one trustworthy?

That’s a really good point, but I find that to be sort of like a double-edged sword. You could have a person being honest, but if you don’t trust that person to do so then you’re more than likely going to take that honesty as dishonesty simply because you don’t trust that person to be honest.
I’d say more things fall into building trust than just honesty, but that’s just me.

I was going to say respect, then I started thinking about trust, but I think if you respect, trust would be a big part of it. You couldn’t respect someone you couldn’t trust. Love comes and goes, waxes and wanes, surges and retreats and all that stuff, and a relationship must weather all those changes. And it can do it if there is respect. Without respect, I think a relationship will eventually be doomed.

A mix of the above:
Respect
Trust
Honesty
The little things that you have in common
authenticity
But most of all and not mentioned yet Love…

Togetherness…...naturally.

Communication and the willingness to communicate…

Honesty,dignity, and integrity.