וַיֹּ֕אמֶר אָנֹכִ֛י אֲשַׁלַּ֥ח גְּדִֽי־עִזִּ֖ים מִן־הַצֹּ֑אן וַתֹּ֕אמֶר אִם־תִּתֵּ֥ן עֵרָב֖וֹן עַ֥ד שָׁלְחֶֽךָ׃
유다가 가로되 내가 내 떼에서 염소 새끼를 주리라 그가 가로되 당신이 그것을 줄 때까지 약조물을 주겠느냐
Rashbam on Genesis
עד שלחך. The reason why we have the “weak” mode, i.e. the conjugation kal instead of the transitive conjugation hiphil, is to indicate that Yehudah would send a messenger to deliver the kid to Tamar. We find the use of the conjugation kal in connection with the sending of gifts especially, as for instance in 32,19 where Yaakov had instructed his messengers to Esau to describe the gift in such terms. (מנחה היא שלוחה) We find it again in verse 23 of our chapter where Yehudah says הנה שלחתי הגדי הזה, “here, I have sent this kid, etc.”
Sforno on Genesis
אם תתן ערבון, if you are prepared to give me such tokens I am willing to sleep with you as you requested.