Lyrically, melodically, and rhythmically, there's a strong resemblance between this and the line "I still love her" in "I Don't Want to Spoil the Party" (specifically Lennon's part, which is the lower of the two):
Of course, the only difference lyrically is the pronoun. As far as melody, both phrases begin with a falling fifth, go back up (a fifth in "Foolish Little Girl" but only a fourth in "I Don't Want to Spoil the Party"), and then ascend a whole step. In terms of rhythm, both parts have long, drawn-out notes (especially compared to the surrounding vocal parts), and the last note has half the value of (most of) the others.
The Beatles were clearly familiar with the Shirelles (they covered "Baby It's You" and "Boys" on Please Please Me), so "Foolish Little Girl" may have had some influence on this part in "I Don't Want to Spoil the Party," even if only subconsciously.