This is a distich from Daniël Heinsius' emblem collection entitled Quaeris quid sit amor? (sometimes also titled: Emblemata amatoria) published c. 1601. You can find the book online at the Emblem Project Utrecht.
Non aliter, quam cum ramum sibi ramus adoptat,
Sic tibi non idem, nec tamen alter, ero.
The vocabulary is keyed to the DCC Latin Vocabulary list. There are only two words in this poem that are not on the DCC list:
adoptō, -āre - choose, select, adopt
rāmus, rāmī m. - branch, bough
aliter: otherwise, differently
alter altera alterum: other of two
cum: with (prep. + abl.); when, since, although (conjunction + subj.)
īdem eadem idem: the same
neque nec: and not, nor; neque . . . neque, neither . . . nor
nōn: not
quam: how?; (after comparative) than
sīc: in this manner, thus; sīc . . . ut: in the same way as
sui, sibi, sē: him- her- itself
sum, esse, fuī: be, exist
tamen: nevertheless, still
tū tuī tibi tē: you (sing.)