In God, we trust. For everyone else, we run the normal verification procedures. The first concerns their capability to deliver or not. The second is in regard to their intention. Can they? Will they?
Capability is easier to assess than intention so let us address this first. You need to:
The simplest way is to find out if they have done this before. You will be able to get some idea in conversation but remember: trust but verify. Do your research, talk to others who have conducted business with them. Happily, these factors are relatively ‘concrete’ and so can be checked quite easily.
There is still the question ...