"'Batach' is one of the Hebrew words the Bible translates as 'trust'. ...
One of the meaning of 'batach' is 'to be careless.'
It's not careless as in irresponsible or impulsive.
It's care-less, as in without any cares or concerns.
If you have a 'batach' kind of trust, you feel free with someone;
you don't have to edit yourself, be vigilant about what you say, or walk on eggshells.
In 'batach', you open up a vulnerable part of yourself to God or another person
without second-guessing or worrying about betrayal.
That's trust."
[Dr. John Townsend, "Beyond Boundaries: Learning to trust again in relationships"]