必有重謝

(we) will be very grateful (if ...)

certainly / must / will / necessarily

to have; there is / (bound form) having; with; -ful; -ed; -al (as in 有意[you3 yi4] intentional)

to repeat / repetition / again / re- / classifier: layer

heavy / serious / to attach importance to

to thank / to apologize / (of flowers, leaves etc) to wither / to decline