There are people, & we all probably know 1 or 2, that have trouble trusting other poeple. But most people only think that it's strange & they don't think about why it is like that, & we do that with so much more things than people's trust issues. For me it's because I'm to trusting to begin with, so I don't always trust my own sense of trust. For others it may be they've trusted the wrong poeple in their past & they were betrayed, & for some it's because they havn't got a fully developed sense of trust.
But trust is an important part of life, especially trust in GOD, Jeramiah 32:6-12. Look at the story of Joeseph in Genesis, David & Goliath, Job, King David, the disciples, and so much more. But GOD also wants us to be trustworthy, Numbers 30:1-2, like Jesus was, & the disciples were.
Part of that in friendships is calling each other out on things that we're doing that is wrong, in a lovingly way, Psalm 55:12-14. & when a friend betrays us it hurtsm but we need to find a way to restore the friendship, including the trust, though it will never be the same as before, especially since one of the worst things to lose is a friend.
And other times it's hard to trust in things, especially when there's no proof to support it or it's not a popular thing to say. A quote that goes along with that is ,"It's easier to believe in a lie that's been told 1000 times, then a truth that's been told once." -Unknown. But there are rare times in life when we need to believe ins something when there's no proof, like with many things about GOD's word, John 20:29-31, that's why throughout the Bible it tells us to trust in GOD.
And when something really bad happens, we blame it on GOD, even though it's not normallyn GOD's fault, & we don't consider that's it's not his fault, that it wasn't his will, & we lose trust in him. I havn't always been a Christian, but I have been through alot of hardships, & not alot of people know about all of them, if they know about any of them. But since I became a Christian one of my favorite Bible verses is Romans 8:28, it tells us that GOD may not make something bad happen, he can make the best out of whats left.
So though life can be hard, wheather it be people who are close to or just circumstances of life, GOD will be there to help out if you ask him to. & it may not happen right away, or when you want it to, but he'll be there to help out.