Yes, some politicians are trustworthy, but not many. A politician's character and track record determine whether or not he or she is trustworthy. I can think of a few politicians whom I personally deem trustworthy. They include Jimmy Carter, Diane Feinstein, Bernie Sanders, and Barrack Obama. I am sure not everyone agrees with my list, but to me, these are examples of honest and trustworthy politicians.
No politician is trustworthy; they are either a politician and will lie, cheat and steal to preserve their own job or they are not truly politicians and will be markedly ineffective in a system that only recognizes thievery and louts. The system is designed to ensure that corruption, greed and deceit are the only way forward.
In this day and age, the political system is nearly entirely corrupt. Politicians say what they are told to get elected in hopes to have a well paying job, fame, and influence upon the world. Politicians are forced to lie, and cheat in order to be elected now and there are few ways around it.
No politician should be considered trustworthy. This is because no human being is fully trustworthy. Politicians need to be consistently called on their record and judged by their record. This is why so many political positions have limited times for office tenure. It is best kept this way so that the people can vote out those they deem untrustworthy.