OK before we declare Aditi/Neha a UDP or a brainless bimbo for thinking Kabir is her killer here is why she thinks so:
1. She overheard that he married her for the money when she went to get her purse right before her accident;
2. She thinks he shot at her car right after causing the accident that killed her mother and nearly killer her. The person shooting at her vehicle had the same checked black & white jacket Kabir had on earlier in the day while telling her he couldn't go with her and while talking on the phone declaring he married her for money.
3. Maybe she reasons that when he killed her he believed that he would inherit her money. But, her lawyers put the money into a trust instead because they were suspicious of Kabir.
Points 1 & 2: Are revealed in June 1 episode during flashback while Aditi/Neha monologues at the Kali Temple.
Point 3 has not be shown but, could be her reasoning behind why Kabir tried to kill her (his motive)... he has not exactly helped his cause since she has returned and given her reason to believe he is interested in anything other than Aditi's money. With "Aditi" back...the money can be transferred from the trust to a joint a/c - giving Kabir access.