you = 你 = nǐ "tai sha le" = too silly = 太 傻 了 = tài shǎ le

you have known the pinyin for "taishale" right? this phrase mainly used in these circmastance: when you don't like someone's clothes expecially he/she asked your opinon about the new clothes he/she wearing.you can say taishale. it means it sucks. o.c. it's only used between acquaintance. (spelling mistake omit it please)

for this meaning , for romantic relationship you should say 小傻瓜（for girls） xiao sha gua or 呆子(for boys) , both mean silly persons.

i think it's "太傻了(tài shǎ le)"

Or it could be"ni hao sha". It's commonly used among couples or close friends.