You can try asking the seller, but s/he is not required to tell you, and might block you for asking.
Or you bid what the item is worth to you, the most you are willing and able to pay for it. If you bid an amount that does equal or exceed the reserve, the "Reserve not met" will disappear from the Listing Page and the Bid History Page (unfortunately the indication that there is a met Reserve got lost in a reformat of the Bid History Page) and the new "current bid" will be the exact amount of the reserve (or less than an increment above it if a prior bidder had a maximum bid just under the reserve).
If the (refreshed) Listing Page continues to say "Reserve not met" after you place your bid, it means your bid (including any hidden maximum) is lower than the reserve price and therefore cannot win that auction, so it is safe to move on (unlike simply being outbid, when a cancellation of the higher bid before the auction ends can make you the winner at the end and obligated to pay, so it is not safe to move on until the auction ends without you as the winner). Even if the seller lowers the reserve, eBay will lower your hidden maximum bid if needed (to $1 below the new reserve) so you can't win unless you rebid an amount that meets the reserve at the time it is placed.
