I'm starting my first Chinese class in a few days, and I was hoping someone could help me write name in Chinese (with a pinyin transliteration because I can't read Chinese characters yet)? My first name is Ren :D
The only person with the surname Ren I can think of that is not Japanese or Chinese is Kylo Ren, whose translated name seems to be 凱(Ky)羅(lo)·忍(Ren). However, you probably shouldn't use 忍 (tolerate, withstand) as your name as it is highly unusual and people would probably think you are a chuuni as it is part of the word 忍者 (Ninja)
In Japanese names, Ren can be Kanji such as 蓮 (lotus) and 錬 (smelt), however, the pronunciation is more like Len rather than Ren.
Ren (任) is a Chinese surname, and its pronunciation is also not the same as the original. It probably won't suit your purpose.
If we are talking about characters that are less common in names, 仁 (benevolence, one of the five virtues in Confucianism) is probably also OK?
The characters pronounced "Ren" in CC-CEDICT are:
人 人 [ren2] /man/person/people/CL:個|个[ge4],位[wei4]/ 亻 亻 [ren2] /"person" radical in Chinese characters (Kangxi radical 9)/ 仁 仁 [ren2] /humane/kernel/ 儿 儿 [ren2] /variant of 人[ren2]/"person" radical in Chinese characters (Kangxi radical 10), occurring in 兒, 兀, 兄 etc/ 壬 壬 [ren2] /ninth of the ten Heavenly Stems 十天干[shi2 tian1 gan1]/ninth in order/letter "I" or Roman "IX" in list "A, B, C", or "I, II, III" etc/ancient Chinese compass point: 345°/nona/ 忍 忍 [ren3] /to bear/to endure/to tolerate/to restrain oneself/ 棯 棯 [ren3] /jujube tree/ 稔 稔 [ren3] /ripe grain/ 腍 腍 [ren3] /be satiated/cooked/good-tasting/ 荏 荏 [ren3] /beefsteak plant (Perilla frutescens)/soft/weak/ 荵 荵 [ren3] /polemonium/ 仞 仞 [ren4] /(measure)/ 任 任 [ren4] /to assign/to appoint/to take up a post/office/responsibility/to let/to allow/to give free rein to/no matter (how, what etc)/classifier for terms served in office, or for spouses, girlfriends etc (as in 前任男友)/ 刃 刃 [ren4] /edge of blade/ 妊 妊 [ren4] /pregnant/pregnancy/ 姙 妊 [ren4] /variant of 妊[ren4]/ 恁 恁 [nen4] /to think/this/which?/how? (literary)/Taiwan pr. [ren4]/ 牣 牣 [ren4] /fill up/to stuff/ 祍 祍 [ren4] /old variant of 衽[ren4]/ 紉 纫 [ren4] /to string/to thread (needle)/ 紝 纴 [ren4] /to weave/to lay warp for weaving/silk thread for weaving/variant of 紉|纫, to sew/to stitch/thread/ 絍 絍 [ren4] /to weave/to lay warp for weaving/variant of 紝|纴[ren4], silk thread for weaving/ 肕 肕 [ren4] /old variant of 韌|韧[ren4]/ 葚 葚 [shen4] /fruit of mulberry/also pr. [ren4]/ 衽 衽 [ren4] /(literary) overlapping part of Chinese gown/lapel/sleeping mat/ 袵 衽 [ren4] /variant of 衽[ren4]/ 訒 讱 [ren4] /(literary) slow in speech/ 認 认 [ren4] /to recognize/to know/to admit/ 軔 轫 [ren4] /brake/ 靭 韧 [ren4] /variant of 韌|韧[ren4]/ 靱 韧 [ren4] /old variant of 韌|韧[ren4]/ 韌 韧 [ren4] /annealed/pliable but strong/tough/tenacious/ 飪 饪 [ren4] /cooked food/to cook (until ready)/ 餁 饪 [ren4] /variant of 飪|饪[ren4]/ 鵀 鵀 [ren4] /hoopoe/
From here, it's possible to choose whatever you consider to be meaningful, and then check http://name.renren.com/ to see if it's actually used, and what gender it's appropriate for. Taking 忍 (suggested by Scharlach Nachtfalter) for example, if we attach an arbitrary surname 王, we find:
人人网上姓名为 王忍 的用户共有 660人，其中 女生20.45%， 男生79.55%
RenRen Wang users called 王忍 together comprise 660 people, among which 20.45% are female and 79.55% are male.
人人网上姓名为 王忍忍 的用户共有 49人，其中 女生55.10%， 男生44.90%
RenRen Wang users called 王忍忍 together comprise 49 people, among which 55.10% are female and 44.90% are male.
(Note, usually Chinese teachers can help you choose a Chinese name.)