There are four broad categories why a potential intelligence asset would betray their affiliations:
Money - Low salary, greedy, in debt, etc.
Ideology - Hates his system, admires ours?
Compromise/Coercion - Blackmail, emotional relationship, etc.
Ego/Excitement - Lonely, looking for a friend, passed over for a promotion. Not appreciated, seeking praise or adventure or personal challenge.
Usually emotions are connected to recruiting an intelligence asset. Here is a list of emotion categories:
Love (Affection, Lust, Longing)
Joy (Cheerfulness, Zest, Contentment, Pride, Optimism, Enthralment, Relief)
Surprise
Anger (Irritation, Exasperation, Rage, Disgust, Envy, Torment)
Sadness (Suffering, Sadness, Disappointment, Shame, Neglect, Sympathy)
Fear (Horror, Nervousness)
When recruiting an intelligence asset there might be various levels of success or failure:
Information Source - Willing to leak information but not carry out any other tasks.
Executive Agent - Will carry out orders such as sabotage, attacks, etc.
Recruiting Agent - Will be willing to recruit others.