deep-rooted suspicion

Translations
глубоко укоренившееся подозрение
His deep-rooted suspicion of strangers makes it hard for him to trust new people.
Его глубоко укоренившееся подозрение к незнакомцам делает ему трудно доверять новым людям.
Definitions
A strong and long-standing feeling of doubt or mistrust towards someone or something, often developed over a long period and difficult to change.