I don't have a belief, but if it were proven I would not be surprised.

If we have been visited and there is no proof of their being here, then they are so advanced we have no idea what we are looking for. They would be so advanced in their technology we could have a room full of them in front of us and we would see nothing, experience nothing. They would have the upper hand, they arrived here.
For all we know they have a library which holds every aspect of our culture in detail. #-D representations of every event that has ever happened. They would know more about us than we have about ourselves.
Any advanced culture would have access to what we call the Planck Space, which means they could have machines we would never experience around us all the time.
If any of these beings ever made themselves present we would not know what to do with them. Given present situation we would do everything to make the world a worse place to live. We are working on this now, why would we change.
Of course, if we have not been visited, then it does not matter to us as to why. We would have no idea what would be acceptable to them or our relation.

It can’t be disproven, of course, but I doubt it.
Depends too, on what you consider ‘life’ to be. Cellular or bacterial activity? Or do you mean evolved forms flying spaceships?
I guess there might be planets with water and gases that can support cellular growth, but any more than that? Nah.

No; the distance is too great and our significance too little..

I personally don't. I'm convinced that there is other life in the universe but not that they come to earth.
We're lucky that we can leave our planet. If there is advanced alien life on larger rocky planets, since we're on the smaller end of the spectrum, they have much more gravity to fight against. If their planet had twice the radius, they would be twice as far from the centre which is 4 times less gravity but the volume would be 8 times greater so they overall fight against twice as much gravity which would mean deep space would be harder to achieve and they would have to go further.
They would need rockets about half a million tons to be able to leave and that doesn't even start to consider how much more they'll need if they want to bring other resources to space and travel lightyears to look at another planet that they don't intent to live on.
Our planet has exited for a third of the life of the universe and we still aremt advanced enough to travel into deep space for long periods of time. It's unlikely that there are nearby planets with life that are older than earth and similar size or smaller and technologically capable of going to other planets and then choosing to come to earth and manipulate anything

You are confusing belief with Faith, actual belief can only apply to theories that have not yet been disproved. This requires evidence.
What you are postulating are leaps of Faith, that not only don't not require evidence but find evidence unnecessary and/or offensive.

I give no thought whatsoever to ufo entities.

Is it possible? I can't even say.

Is it likely? Extremely not so.

Is it important? No, it can safely be put on a far back burner or even the round file until there is an alien prepared to interact with us, answer questions and perhaps open an embassy here.

It's pretty stupid but no more stupid than religion.

No.

It is easy for me to believe that there could be - and most likely is - other life out there. The universe is so incomprehensibly big. It seems ridiculous to assume that we are the only ones.

As to any of those life forms visiting us, though, I am extremely skeptical. The time, distance, and conditions of such travel seem to make such an event less likely than the proverbial snowball's chance in hell.

A little part of me is miffed, too, that anyone would suppose that the greater human accomplishments needed outside help - as though we're not good enough to accomplish these things on our own!