Lull (one) into a false sense of security American British cliché
To persuade one to feel safe but still exist some threats or dangers
Don't let the weakness of your opponent lull you into a false sense of security. They may counter-attack at any moment of the match.
Getting fully vaccinated lulled many people into a false sense of security, in reality, some of them got covid 19 again after all.
I think the first victory in English Rhetoric Competition has lulled her into a false sense of security and made her neglect the practice.
The verb "lull" should be conjugated according to its tense.