Kourtney Kardashian reportedly ''trusts'' Sofia Richie with her children.

The 39-year-old reality star has Mason, eight, Penelope, five, and Reign, three, with her former partner Scott Disick, and after the hunk and his brood have been spending more quality time with his new girlfriend Sofia Richie - who is the daughter of music legend Lionel Richie - it has been claimed Kourtney is happy with the way the new relationship is progressing.

A source told People magazine: ''It helps that Kourtney now trusts Sofia. The kids are allowed to spend time with her. Sofia likes having them and helps Scott. So far, the kids are giving Kourtney good reports about Sofia.

''Sofia has shown over and over again that she is willing to stay with Scott even when things are not great - but Scott is doing well lately. [He] isn't really partying and spends a lot of time with his kids.''

Sofia, 19, and Scott, 34, have been romantically linked since last year, and it was recently reported the couple are ''talking about moving in together permanently'' as their relationship continues to heat up.

An insider said: ''Scott and Sofia are still going strong and have gotten more serious the past few months. They have definitely had their ups and downs, but lately everything has been really good between them.''

The romance is even said to be getting the stamp of approval from Sofia's dad Lionel, who previously claimed he was ''scared to death'' at the thought of his daughter dating the 'Keeping Up with the Kardashians' star.

A separate source said: ''Lionel Richie has finally warmed up and accepted the fact that Scott Disick is dating his daughter Sofia.

''Lionel had a hard time with the situation at first, and warned Sofia to end the relationship before she got in too deep with Scott, but he now has finally come full circle.''