1. letter
2. mail
3. to trust
4. to believe
5. to profess faith in
6. truthful
7. confidence
8. trust
9. at will
10. at random

classifier: 封

1. to assign
2. to appoint
3. to take up a post
4. office
5. responsibility
6. to let
7. to allow
8. to give free rein to
9. no matter (how, what etc)
10. classifier for terms served in office, or for spouses, girlfriends etc (as in 前任男友)