I've bought an butterfly knife on aliexpress with a seller called Zhang Zefeng. Two days ago i've received the tracking number UA732217498YP but it can't be found whenever i try to track my parcel. I messaged the saller and he replied me with this
"Hello dear friend,

Thanks for your good patience. Please don't worry. Your parcel was posted by default economical air mail without tracking number. This number is a code which we get from our shipping agency, it can indicate that your parcel has shipped.

Actually, the speed of shipping which has tracking No is slowly than which has not. Because there are more procedures to do for showing the parcel status. Besides, It is a long distance from China to your local region. So the information of your parcel status will not present in time. Therefore, I sent your parcel without tracking No. We will receive the confirmation information from logistics. I will responsible for you until you received your parcel.

Any problem on the shipping or items, please feel free to contact with me. I will be glad to help you.

Best Rergards"

Should i trust him? Or just wait untill i can open a dispute?