Easiest way is to pay a little to a known and respected verification service, such as Derek Ross's nostrplebs.com or nostrcheck.me or zaps.lol

The best way is to host your own Nostr verification on a domain that you own. So say you own SeyrBitcoin.com, then you could run a Nostr verifier that says Robyn@SeyrBitcoin.com is legit and linked to your npub.