It’s best to tell him he smells in a way that he understands but also encourages him to make a change.
He shouldn’t be made to feel as though he is the worst person in the world for having an odor.
The most effective way to tell him he smells is when you do it in a way that he gets the point without feeling as though he is less than a person.
One of the best ways to go about this is to compliment him on something first and keep this up for a little while.
If you have noticed that he does something really well or there is something he wears that really looks good on him, compliment him on that consistently.
Do your best to really show how much you love and appreciate whatever it is that you find to look good on him or whatever personality trait of his that you love.
Once you have used this approach consistently and you notice that he has been grateful for it, you can then approach the issue of how he smells.
You have now built him up by giving him compliments about things he is good at or a way he looks, so he is feeling good and is in a good mental space.
He is feeling like you look out for him and you are taking notice of what he is good at.
This is great.
You have put him in a good place mentally where he now trusts you and your opinion.
Now, in order to address the issue that he smells, you can use a tactic that gets the point across without having to be so blunt.
It would also be a tactic that helps to remedy the problem as opposed to simply stating it.
This tactic would involve how you lead by your own example.
If you have noticed that he smells because he just doesn’t launder his clothes and tends to wear the same smelly, sweaty clothes all the time, you can tell him that you want to do laundry and you would love for him to help you out with it.
You also tell him to bring his dirty clothes that need washing.
If he agrees, the both of you can enjoy your time together as you both do laundry.
At the end of the process, you can take up one of his pieces of clothing and smell it.
You can let him know that you love that fresh and clean smell on his clothes.
Tell him that it is so much sexier and hot on him than when he is wearing sweaty, dirty clothes.
This approach can be very effective because you are conveying the message that his clothes do smell but that you would love it when his clothes are clean and laundered.
Being that you have already built him up into a positive mental space by giving him compliments up until this point and you have just spent this awesome time together laundering your clothes together, he would be at a much better mental space to understand and accept your request.
Hence, he would take the news a lot better.
If you proceed to do laundry on a consistent basis with him so that he gets used to it, he may get to the point where he starts doing it on his own because he knows that you prefer that he wear clean clothes.
In essence, by showing him through example that doing laundry is something you hold dear, he will be able to understand its significance.
The next time he thinks about wearing dirty clothes, he would most likely remember the last time he did laundry with you and that may motivate him to clean those dirty clothes.