Linda, I looked through all the books I have but did not find a listing for this marriage. I did do a bit of research on the internet. You may have this already but in case you don't...
1830 Warren co., p. 71 Philip Sears 0210001-1120001
1830 Allen Co., p. 78 William Hammett, sr. 00203001-101101 Diana Hammett no males- 0121001 William, Jr 00001-1001
1840 Warren, p. 78 Jno Sears 3200001-001001 p. 81 Philip Sears 00012001-00100001
1850 Dist 2, Warren, p. 84b John sears, 45, vA Francis, 44, SC Wm T., 19 James D., 17 John M., 15 George R., 13 Robert L., 10 Ann F., 8 Nancy J., 4 Maria E., 2
1860 Pct. 1, Dallas, TX p. 300 Jn. Sears, 55, VA Frances, 55, SC Robt. L., 20, KY Ann F., 18 Marie E., 12 Saml. m., 10, TX Geo. R., 20, KY Jn. M., 22, KY
There are several Sears living in Allen Co. in 1830-40 but I have listed John and Philip in Warren co. since John obviously shows up there in 1850. This Philip is certaily old enough to be the father of John but it is odd that none of John's sons are named Philip. It's a place to start. Of the Hammetts in Allen Co. I think it's a good bet that William Sr. is the father of your Frances. She has named one of her first sons William.
Here's my suggestion. i would write to the Warren and Allen co. courthouses and see if they have 1. a record of the marriage of William and Frances. 2. If they have records of a will and/or probate for Philip Sears and William Hammett, sr. A will might name any beneficiaries.
Allen 201 W. Main Scottsville, KY 42164
Warren 429 E. 10th Bowling Green, KY 42101
Be sure to include a SASE so that can respond easily. Good Luck!