betray    kugambanira
(a secret) guhemuka
(one who) umuguranyi
En-En dictionary 
kugambanira (-gambaniye)     v    to betray
secret    ibānga
(to betray) kumena ibānga, guhemuka
(one who can't keep) igihururu
En-En dictionary 
guhemuka (-hemutse)     v    1. to fail to keep one's word, 2. to disappoint, 3. to betray a secret
ubugambanyi   8  class 8
singular: ubu-
  
betrayal, treason (from kugambanira)
umuguranyi (aba-)     1  class 1
singular: umu-
plural: aba-
  
traitor, one who betrays, slave trader
betrayal    ubugambanyi
En-En dictionary