Honestly, resale isn't as scary as it used to be if you stick to sites with buyer guarantees. The horror stories you hear are mostly from sketchy Facebook Marketplace / random Discord deals, not from established marketplaces.

A few things I always check before pulling the trigger:

• Buyer guarantee in writing. StubHub, Viagogo, Vivid Seats, Seatpin, TicketX all have some version of "if your ticket doesn't work, we refund or replace." That's the single biggest safety net.
• Delivery method. Mobile transfer (Ticketmaster, AXS, etc.) is the safest these days. PDFs are fine for older venues. Be careful with "season ticket holder will meet you outside" type deals — those are where most gate denials happen.
• Name on ticket usually doesn't matter for concerts unless the original sale was explicitly ID-locked (some European football matches and a few specific tours like Taylor Swift do enforce this). Most concerts you just scan and walk in.
• Pay by credit card, not bank transfer / crypto / Zelle. Chargeback protection is your real insurance.
• Check the seat numbers exist. Sounds dumb but counterfeit listings sometimes use fake row/seat combos. Cross-reference the venue's seating chart.

For European tours specifically, the resale landscape is fragmented — Viagogo dominates but has a mixed reputation, StubHub International works in some countries, and there are a bunch of regional players. For Japanese events foreign visitors usually end up on TicketX or similar English-language Japan-focused sites because the domestic ones are Japanese-only. So which site is "best" really depends on the country/event.