1. 
[syn: trust, trustingness, trustfulness]
The Collaborative International Dictionary of English v.0.48:
Trustful \Trust"ful\, a.
   1. Full of trust; trusting.
      [1913 Webster]
   2. Worthy of trust; faithful; trusty; trustworthy.
      [1913 Webster] -- Trust"ful*ly,adv. -- Trust"ful*ness,
      n.
      [1913 Webster]
WordNet (r) 3.0 (2006):
trustfulness
    n 1: the trait of believing in the honesty and reliability of
         others; "the experience destroyed his trust and personal
         dignity" [syn: trust, trustingness, trustfulness]
         [ant: distrust, distrustfulness, mistrust]