As someone personally dealing with impostor-ish thoughts, I can certainly attest that I feel much better when being told by a manager/client something like "I'm

As someone personally dealing with impostor-ish thoughts, I can certainly attest that I feel much better when being told by a manager/client something like "I'm not at all sure you can address this problem for me efficiently. Can you?", rather than "I have full faith in your skills, go forth and bring me results".