How do you handle giving feedback to an interviewee who seemed overconfident during the interview?

I have always find it useful to create a friendly environment with the interviewee where they feel free to be themselves. Initially cultivating a friendly environment is a first step 'starting from saying thank you for arriving early" the timing therefore will create itself " interviews should always be conversational not interrogative" candidates are human beings which means they understand they can make mistakes" so it's always good post the interview to ask how did they feel? therefore provide feed back by first stating their strong points then move to areas of improvement.

Tone should be always formal and encouraging and highlight scenarios where they did exceptionally well. gradually highlight areas of improvement.

Start with positive feedback by mentioning their strengths. Next, address areas where improvement is needed and provide specific reasons for any concerns or why the candidate may not be a fit for the role. While the candidate may initially react defensively to criticism, being clear can prompt them to reflect on their performance and make necessary improvements. If the decision is based on factors like salary expectations, clearly communicate this as well. Even confident candidates may reconsider their stance when presented with honest feedback. Overall, ensure your feedback is respectful and aimed at helping the candidate grow professionally, whether they are successful in this instance or in future opportunities.

focused feed on actual real time scenario post the interview, I do think people actually relate better when we make examples about ourselves so that they don't take it like a personal attack, is always good to make references about our past similar experience like a shared common experience.

First, discuss the interview results with hiring managers to gather detailed feedback that you can clearly explain. If you decide to reject the candidate, prepare key improvement points to discuss. If the candidate disputes feedback, acknowledge their perspective while explaining the hiring team's insights. If the rejection is due to salary, state this clearly. Give detailed feedback if the candidate requests it; otherwise, respect their decision if they're not interested.

Actionable advice, is always pivotal to let the interview know about always room for important, this can include tools available online where you engage with other people in real time especially on public speaking where other team mates give you advice on how you performed on your speech delivery.

Is always good to offer yourself as a support system for the future this shows humility and care on candidates ends and speaks volumes on companies culture

After rejecting a candidate, express that you're available to support them with any HR-related questions or concerns. Offer to stay in touch and keep them informed about future opportunities that may align with their skills and experience.

My perspective can be a bit different because when an interviewee is over confident it shows the Job post was clear and not over sold in a sense that the candidate is sure to because the right candidate, I like to interview people who are sure that they will get the job as long as the over confident doesn't seem like arrogance. For the feedback to show the candidate that they were overconfident, I can ask open ended questions that will allow them to introspect how questions were answered.