That depends on whether you're talking about the Rene of Paris Hi Fashion line (ROP) and Noriko palette, or the one for Amore, which is a bit more conservative.
In the Noriko and ROP lines: your best bet is probably going to be something like 12FS8 (Shaded Praline).
In the Amore lines: there isn't a particularly good rooted blonde that is analogous to the Amore Creamy Toffee-R, which is slightly ashier than its ROP / Noriko counterpart. Here again, your closest bet is probably going to be the 12FS8.
Another option to consider is the 27T613S10 (Shaded Sun), which will have a fairly neutral blonde on top (courtesy of the platinum blended into the strawberry in the top of the wig) with baby-blonde tips, similar to hair that has been bleached by the sun.