Private key lost

I’m Alamin . I’m lost my trust wallet private key . So Please give me a way . . How to come back my private key

We have no way to retrieve this for you. This is a mandatory backup that you need to do upon wallet creation.
https://community.trustwallet.com/t/lost-recovery-phrase-or-private-key/221/2

Do you still have the wallet installed on your phone?

If yes go to Wallets > Select your wallet > Export recovery phrase

If you lost the backup words and you also don’t have the wallet installed on any device then Im afraid there is no way to get that acces back