committed in relative isolation, thus, it is usually only the victim who can testify with regard to the fact of the forced sexual intercourse.148 Hence, the probative value of MMM and OOO's testimonies rest not on whether they actually witnessed the rape but on whether their declarations were in harmony with KKK's narration of the circumstances, preceding, subsequent to and concurrent with, the rape incidents. MMM and OOO's testimonies substantiated significant points in KKK's narration. MMM heard KKK shouting and crying: "Eddie, don’t do that to me, have pity on me"149 on the night of October 16, 1998 shortly after KKK and the accused-appellant went to their conjugal bedroom. When MMM went upstairs to check on her mother, the accused-appellant admonished her for meddling. Frustrated to aid her mother who persistently cried, MMM kicked the door so hard the accused-appellant was prompted to open it and rebuke MMM once more. OOO heard all these commotion from the room downstairs. MMM then saw her mother crouched on the bed, crying, with her hair disheveled while her tom panty lay on the floor. After a brief struggle with the accused-appellant, MMM and KKK were finally able to escape and retreat to the children's bedroom where KKK narrated to her daughters: "[Y]our father is an animal, a beast; he forced me to have sex with him when I'm not feeling well. " KKK gave a similar narration to MMM and OOO the following night after the accused-appellant barged inside the children's bedroom. The couple had an argument and when MMM tried to interfere, the accused-appellant ordered her and OOO to get out after bragging that he can have sex with his wife even in front of the children because he is the head of the family. The girls then stayed by the staircase where they afterwards heard their mother helplessly crying and shouting for the accused-appellant to stop. Indeed, the testimonies of KKK, MMM and OOO coherently depicted that the accused-appellant, through the use of force and intimidation, had non-consensual and forced carnal knowledge of his wife, KKK on the nights of October 16 and 17, 1998. KKK's helpless screams and pleas from inside the bedroom coupled with her verbal and physical resistance were clear manifestations of coercion. Her appearance when MMM saw her on the bed after the accused appellant opened the door on October 16, 1998, her conduct towards the accusedappellant on her way out of the room, and her categorical outcry to her children after the two bedroom episodes - all generate the conclusion that the sexual acts that occurred were against her will. Failure to immediately report to the police authorities, if satisfactorily explained, is not fatal to the credibility of a witness. The testimonies of KKK and her daughters cannot be discredited merely because they failed to report the rape incidents to the police authorities or that KKK belatedly filed the rape charges. Delay or vacillation by the victims in reporting sexual assaults does not necessarily impair their credibility if such delay is satisfactorily explained.150 At that time, KKK and her daughters were not aware that a husband forcing his wife to submit to sexual intercourse is considered rape. In fact, KKK only found out that she could sue his husband for rape when Prosecutor Benjamin Tabique, Jr. (Prosecutor Tabique) told her about it when she filed the separate charges for grave threats and physical injuries against the accused-appellant.151