All who come to faith in Christ are now separated out from the world to belong to Him (His Body - The Church) - they are His "bethrothed"  they are destined to be joined (married) to Him - when He comes for them either at their death or the rapture - the End of the Church.
 
BUT.... only those who deny themselves, pick up their crosses to follow Him, love Him more than anyone else  AND..... remain faithful to Him to end - while living..... become His bride.

The rest will enter heaven as the "redeemed." His bride are those who have proven themselves "worthy" of Him. Many are called into His Body - But His bride is chosen out of His Body