SELECT T1.name FROM useracct AS T1 JOIN trust AS T2 ON T1.u_id  =  T2.source_u_id GROUP BY T2.source_u_id ORDER BY avg(trust) DESC LIMIT 1
Find the name of the source user with the highest average trust score.
[Schema (values) (types)]: | epinions_1 |  item : i_id (text) , title (number) | review : a_id (text) , u_id (number) , i_id (text) , rating (number) , rank (number) | useracct : u_id (text) , name (number) | trust : source_u_id (text) , target_u_id (number) , trust (text);