Jennifer Lopez is reportedly ready to marry for the fourth time. The 42-year-old singer, who parted ways with third husband Marc Anthony last July, apparently wantsto marry her boyfriend Casper Smart. ''She's telling friends she wants to marry Casper. She'scertain she wants to be with Casper forever, a source told Us Weekly. While announcing herupcoming world tour at a press conference, Lopez said Smart, her partner of six months, willplay a crucial role in putting the show together. ''I'm working with [choreographer] Jamie King,and also Casper Smart. It's going to be an amazing, amazing show.''