A source tells PEOPLE the Migos rapper has been pulling out all the stops to win back Cardi B

Cardi B and Offset are back together — but it took some hard work on the rapper’s end to get there.

“He has been pursuing her hard and trying to convince her to get back together with him since the day they split,” a source close to the couple tells PEOPLE exclusively.

Leaving court in Queens, New York on Thursday morning after her assault case was adjourned until April 4, the Grammy-nominated rapper was asked by reporters if she was “back with Offset” after the two split late last year amid rumors of infidelity.

“We working things out, baby,” Cardi, 26, coyly replied as she slid on her sunglasses and made her way to a waiting car.

Cardi B Strip Club Fracas, New York, USA - 31 Jan 2019
Cardi B
| Credit: Frank Franklin II/AP/REX/Shutterstock

According to the source, Offset, 27, has “promised” Cardi he “will behave” going forward.

The reconciliation news comes a little more than a month after the rapper announced on Instagram that she and the Migos rapper were calling it quits after 15 months of marriage.

Premios Billboard de la Musica Latina - Season 2018
Cardi B and Offset
| Credit: John Parra/Telemundo/NBCU Photo Bank via Getty Images

In a Dec. 5 video, which has since been deleted, Cardi shared that the pair — who share 6-month-old daughter Kulture — “grew out of love” but were still “really good friends and … really good business partners.”

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“We got a lot of love for each other but things just haven’t been working out between us for a long time,” she added. “It might take time to get a divorce and I’m going to always have a lot of love for him because he is my daughter’s father.”

Jeremy Scott show, Front Row, Spring Summer 2019, New York Fashion Week, USA - 06 Sep 2018
Credit: Swan Gallet/WWD/REX/Shutterstock

Amid infidelity rumors that continued to plague their public relationship, Offset admitted, “I was partaking in activity that I shouldn’t have been partaking in, and I apologize. You know what I’m saying? For breaking your heart, for breaking our promise, for breaking God’s promise and being a selfish, messed up husband.”

The stars reunited during a vacation in Puerto Rico days after Offset pleaded for Cardi’s forgiveness in a video message, and crashed her performance during Rolling Loud festival with 2,000 stem roses that spelled out “Take Me Back Cardi” to beg her to reignite their romance